Intervertebral spacer device having recessed notch pairs for manipulation using a surgical tool

ABSTRACT

Instrumentation for implanting an artificial intervertebral disc includes static trials and a dynamic trial for determining the appropriate size of disc to be implanted, static trial holders for manipulating the static trials, inserter/impactors for inserting and removing the static trials and for inserting the artificial intervertebral discs, repositioners/extractors for repositioning and extracting the static trials or the artificial intervertebral discs, and a leveler for setting the proper position of the artificial intervertebral disc. Methods for using the same are also disclosed. Features for artificial intervertebral discs and intervertebral spacer devices useful for manipulation by the instrumentation are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/716,360, (filed Mar. 9, 2007), entitled “IntervertebralSpacer Device Having Engagement Hole Pairs”, (“the '360 application”),which is a continuation application of U.S. patent application Ser. No.10/663,492, (filed Sep. 16, 2003), entitled “Intervertebral SpacerDevice Having Engagement Hole Pairs for Manipulation Using a SurgicalTool”, now U.S. Pat. No. 7,223,291 (“the '291 patent”), which is acontinuation-in-part of U.S. patent application Ser. No. 10/282,356(filed Oct. 29, 2002) entitled “Instrumentation and Methods for use inImplanting an Artificial Intervertebral Disc”, now U.S. Pat. No.7,169,182 (“the '182 patent”) and a continuation-in-part of U.S. patentapplication Ser. No. 10/309,585 (filed Dec. 4, 2002) entitled “StaticTrials and Related Instruments and Methods for use in Implanting anArtificial Intervertebral Disc”, now U.S. Pat. No. 7,115,132 (“the '132patent”) and a continuation-in-part of U.S. patent application Ser. No.10/425,267 (filed Apr. 29, 2003) entitled “Wedge Plate Inserter/Impactorand Related Methods for use in Implanting an Artificial IntervertebralDisc”, now U.S. Pat. No. 7,235,081 (“the '081 patent”), which is acontinuation-in-part of the '182 patent. The '182 patent is acontinuation-in-part of U.S. patent application Ser. No. 10/256,160(filed Sep. 26, 2002) entitled “Artificial Intervertebral Disc HavingLimited Rotation Using a Captured Ball and Socket Joint With a SolidBall and Compression Locking Post”, now U.S. Pat. No. 6,989,032 (“the'032 patent”), which is a continuation-in-part of U.S. patentapplication Ser. No. 10/175,417 (filed Jun. 19, 2002) entitled“Artificial Intervertebral Disc Utilizing a Ball Joint Coupling”, (“the'417 application”), which is a continuation-in-part of U.S. patentapplication Ser. No. 10/151,280 (filed May 20, 2002) entitled “TensionBearing Artificial Disc Providing a Centroid of Motion Centrally LocatedWithin an Intervertebral Space”, (“the '280 application”), which is acontinuation-in-part of U.S. patent application Ser. No. 09/970,479(filed Oct. 4, 2001) entitled “Intervertebral Spacer Device Utilizing aSpirally Slotted Belleville Washer Having Radially Extending Grooves”,now U.S. Pat. No. 6,669,730 (“the '730 patent”), and acontinuation-in-part of U.S. patent application Ser. No. 10/140,153(filed May 7, 2002) entitled “Artificial Intervertebral Disc Having aFlexible Wire Mesh Vertebral Body Contact Element”, (“the '153application”), now abandoned. The '132 patent (detailed above) is acontinuation-in-part of the '182 patent, and the '730 patent is acontinuation-in-part of U.S. patent application Ser. No. 09/968,046(filed Oct. 1, 2001) entitled “Intervertebral Spacer Device Utilizing aBelleville Washer Having Radially Extending Grooves”, (“the '046application”), now abandoned, and the '153 application is acontinuation-in-part of the '730 patent (detailed above) as well as U.S.patent application Ser. No. 10/128,619 (filed Apr. 23, 2002) entitled“Intervertebral Spacer Having a Flexible Wire Mesh Vertebral BodyContact Element”, now U.S. Pat. No. 6,863,689, (“the '689 patent”),which is a continuation-in-part of both U.S. patent application Ser. No.09/906,119 (filed Jul. 16, 2001) and entitled “Trial IntervertebralDistraction Spacers”, now U.S. Pat. No. 6,607,559, (“the '559 patent”)as well as U.S. patent application Ser. No. 09/982,148 (filed Oct. 18,2001) and entitled “Intervertebral Spacer Device Having Arch ShapedSpring Elements”, now U.S. Pat. No. 6,673,113, (“the '113 patent”). Allof the above mentioned applications are hereby incorporated by referenceherein in their respective entireties.

FIELD OF THE INVENTION

This invention relates generally to systems and methods for use in spinearthroplasty, and more specifically to instruments for distracting anintervertebral space, inserting and removing trial artificialintervertebral discs, and inserting, impacting, repositioning, levelingand extracting artificial intervertebral discs, and methods of usethereof, and also more specifically to intervertebral spacer devices andartificial intervertebral discs having features rendering them suitablefor manipulation thereby.

BACKGROUND OF THE INVENTION

The bones and connective tissue of an adult human spinal column consistsof more than twenty discrete bones coupled sequentially to one anotherby a tri-joint complex that consists of an anterior disc and the twoposterior facet joints, the anterior discs of adjacent bones beingcushioned by cartilage spacers referred to as intervertebral discs.These more than twenty bones are anatomically categorized as beingmembers of one of four classifications: cervical, thoracic, lumbar, orsacral. The cervical portion of the spine, which comprises the top ofthe spine, up to the base of the skull, includes the first sevenvertebrae. The intermediate twelve bones are the thoracic vertebrae, andconnect to the lower spine comprising the five lumbar vertebrae. Thebase of the spine is the sacral bones (including the coccyx). Thecomponent bones of the cervical spine are generally smaller than thoseof the thoracic spine, which are in turn smaller than those of thelumbar region. The sacral region connects laterally to the pelvis. Whilethe sacral region is an integral part of the spine, for the purposes offusion surgeries and for this disclosure, the word spine shall referonly to the cervical, thoracic, and lumbar regions.

The spinal column is highly complex in that it includes these more thantwenty bones coupled to one another, housing and protecting criticalelements of the nervous system having innumerable peripheral nerves andcirculatory bodies in close proximity. In spite of these complications,the spine is a highly flexible structure, capable of a high degree ofcurvature and twist in nearly every direction.

Genetic or developmental irregularities, trauma, chronic stress, tumors,and degenerative wear are a few of the causes that can result in spinalpathologies for which surgical intervention may be necessary. Withrespect to the failure of the intervertebral disc, and the insertion ofimplants and/or height restorative devices, several methods and deviceshave been disclosed in the prior art that achieve immobilization and/orfusion of adjacent bones by implanting artificial assemblies in or onthe spinal column. More recently, the development of non-fusion implantdevices, which purport to permit continued natural movement in thetri-joint complex, have provided great promise as a preferablyalternative to fusion devices. The region of the back that needs to becorrected, as well as the individual variations in anatomy, determinethe appropriate surgical protocol and implantation assembly. Generally,the preparation of the intervertebral space for the receipt of fusion ornon-fusion devices involves removing the damaged disc material andthereafter distracting the adjacent vertebral bones to their appropriatedistance apart. Once the proper height of the intervertebral space isrestored, the fusion or non-fusion device can be implanted.

It is an object of the invention to provide artificial intervertebraldisc and intervertebral spacer device features, as well asinstrumentation and methods, that enable surgeons to more accurately,easily, and efficiently prepare the intervertebral space and implantfusion or non-fusion devices. Other objects of the invention notexplicitly stated will be set forth and will be more clearly understoodin conjunction with the descriptions of the preferred embodimentsdisclosed hereafter.

SUMMARY OF THE INVENTION

The preceding objects are achieved by the invention, which includesartificial intervertebral disc and intervertebral spacer device featuressuitable for manipulation thereof by surgical instrumentation, andfurther includes static trial artificial intervertebral discs (sometimesreferred to herein as a “static trial”), static trial artificialintervertebral disc holders (sometimes referred to herein as “statictrial holders”), a dynamic trial artificial intervertebral disc(sometimes referred to herein as a “dynamic trial”), artificialintervertebral disc inserter/impactors (sometimes referred to herein as“inserter/impactors”), an artificial intervertebral discrepositioner/extractor (sometimes referred to herein as a“repositioner/extractor”), and an artificial intervertebral disc leveler(sometimes referred to herein as a “leveler”).

More particularly, the features, systems, and methods disclosed hereinare intended for use in spine arthroplasty procedures, and specificallyfor use with the features, systems, and methods described herein inconjunction with the features, systems, and methods described in the'182, '132, '081 and '032 patents and U.S. Pat. No. 7,160,327 (“the '327patent”), as well as those described in U.S. patent application Ser. No.09/906,127 (filed Jul. 16, 2001) entitled “Insertion Tool For Use WithIntervertebral Spacers” (“the '127 application”), now abandoned, whichis hereby incorporated by reference herein. However, it should beunderstood that the features, systems, and methods described herein arealso suitable for use with other features, systems, and methods withoutdeparting from the scope of the invention.

For example, while the static trials described herein are primarilyintended for use in determining the appropriate size of particularembodiments of the artificial intervertebral disc implants described inthe '032 and '327 patents to be implanted (or whether a particular sizecan be implanted) into the distracted intervertebral space, they canalso be used for determining the appropriate size of any other suitablyconfigured orthopedic implant or trial to be implanted (or whether aparticular size can be implanted) into the distracted intervertebralspace. They can also be used to distract an intervertebral space (e.g.,in the same manner in which the trial spacers in the '127 applicationare used as described in the '127 application).

And, for example, while the static trial holders described herein areprimarily intended for use in holding, inserting, removing, andotherwise manipulating the static trials described herein, they can alsobe used for manipulating any embodiment of the trial spacers describedin the '127 application (also referred to therein and herein asdistraction spacers), and can also be used for manipulating any othersuitably configured orthopedic device.

And, for example, while the dynamic trial described herein is primarilyintended for use in distracting an intervertebral space according to theprocedures described herein and/or for determining the appropriate sizeof particular embodiments artificial intervertebral disc implantsdescribed in the '032 and '327 patents to be implanted (or whether aparticular size can be implanted) into the distracted intervertebralspace, it can also be used for distracting an intervertebral spaceaccording to other procedures and/or for determining the appropriatesize of any other suitably configured orthopedic implant or trial to beimplanted (or whether a particular size can be implanted) into thedistracted intervertebral space.

And, for example, while the inserter/impactors described herein areprimarily intended for use in holding, inserting, removing, impacting,extracting, and otherwise manipulating particular embodiments of theartificial intervertebral disc implants described in the '032 and '327patents, they can also be used for manipulating any other suitablyconfigured orthopedic implant or trial.

And, for example, while the repositioners/extractors described hereinare primarily intended for use in repositioning and/or extracting and/orotherwise manipulating particular embodiments of the artificialintervertebral disc implants described in the '032 and '327 patents,they can also be used for manipulating any other suitably configuredorthopedic implant or trial.

And, for example, while the leveler described herein is primarilyintended for use in setting the proper position of, and/or otherwisemanipulating, particular embodiments of the artificial intervertebraldisc implants described in the '032 and '327 patents, it can also beused for manipulating any other suitably configured orthopedic implantor trial.

While the instrumentation described herein (e.g., the static trials,static trial holders, dynamic trial, inserter/impactors,repositioners/extractors, and leveler) will be discussed for use withthe artificial intervertebral disc of FIGS. 13-20, such discussions aremerely by way of example and not intended to be limiting of their uses.Thus, it should be understood that the tools can be used with any of theartificial intervertebral discs disclosed in the '032 and '327 patents,or any other artificial intervertebral disc having (or being modifiableor modified to have) suitable features therefor. Moreover, it isanticipated that the features of the artificial intervertebral disc(e.g., the angled flat surfaces and accompanying holes and inwardlyfacing baseplate surfaces) and/or the static trials (e.g., thecylindrical trunks and angled flat surfaces and opposing notches andaccompanying holes) that are used by the tools discussed herein to holdand/or manipulate these devices (such features, it should be noted, werefirst shown and disclosed in the '182, '132, '081, '032 and '327patents) can be applied, individually or collectively or in variouscombinations, to other trials, spacers, artificial intervertebral discsor other orthopedic devices as stand-alone innovative features forenabling such trials, spacers, artificial intervertebral discs, or otherorthopedic devices to be more efficiently and more effectively heldand/or manipulated by the tools described herein or by other toolshaving suitable features. In addition, it should be understood that theinvention encompasses artificial intervertebral discs, spacers, trials(static or dynamic), and/or other orthopedic devices, that have one ormore of the features disclosed herein, in any combination, and that theinvention is therefore not limited to artificial intervertebral discs,spacers, trials, and/or other orthopedic devices having all of thefeatures simultaneously.

More particularly with regard to the static trials described herein, aplurality of static trials are provided primarily for use in determiningthe appropriate size of an artificial intervertebral disc to beimplanted (or whether a particular size of the artificial intervertebraldisc can be implanted) into the distracted intervertebral space (e.g.,the artificial intervertebral disc 160 of FIGS. 13-20). Preferably, foreach artificial intervertebral disc to be implanted, a plurality ofsizes of the artificial intervertebral disc would be available. That is,preferably, a plurality of the same type of artificial intervertebraldisc would be available, each of the plurality having a respective widthand depth dimension combination that allows it to fit within acorrespondingly dimensioned intervertebral space. For example, theplurality of artificial intervertebral discs could include artificialintervertebral discs having widths being either 35 mm or 40 mm, anddepths ranging from 14 mm to 18 mm in 1 mm increments, for a total of 10discs. Accordingly, preferably, each of the plurality of static trialsfor use with a particular plurality of differently sized artificialintervertebral discs would have a respective width and depth dimensionset corresponding to the width and depth of a respective one of theplurality of differently sized artificial intervertebral discs. Forexample, the plurality of static trials for use with the set ofartificial intervertebral discs described for example could includestatic trials having widths being either 35 mm or 40 mm, and depthsranging from 14 mm to 18 mm in 1 mm increments, for a total of 10 statictrials. It should be understood that the artificial intervertebral discsand/or the static trials can be offered in a variety of dimensionswithout departing from the scope of the invention, and that thedimensions specifically identified and quantified herein are merelyexemplary. Moreover, it should be understood that the set of statictrials need not include the same number of trials for each artificialintervertebral disc in the set of artificial intervertebral discs, butrather, none, one, or more than one trial can be included in the trialset for any particular artificial intervertebral disc in the set.

Each of the plurality of static trials preferably further includesfeatures that can be used by the static trial holders (described below),the inserter/impactors (described below), and therepositioners/extractors (described below). With regard to a featurethat can be used by the static trial holder, each static trialpreferably includes a recess that can be engaged by the opposingsemicircular extents of the static trial holder. Preferably, this recessforms a perimetrical groove (a groove that extends around at least aportion of the perimeter of the static trial, e.g., an annular groove)that establishes a trunk (e.g., a cylindrical trunk) between thebaseplates of the static trial, such that the baseplates extend asflanges from either end of the trunk. Accordingly, preferably, theopposing semicircular extents each have a thickness smaller than thewidth of the annular groove, and as such fit into the annular groove togrip the cylindrical trunk between them.

Additional features that can be used by the static trial holders include(on any static trial surface that faces the desired engagement approachdirection of the static trial holder, e.g., on each of the anteriorlyfacing and anterior-laterally facing flat surfaces of the static trialas described below) opposing recesses, preferably formed as upper andlower notches, an upper notch in the upper baseplates and a lower notchin the lower baseplate. Preferably, the notches are sized so that theopposing notches of each pair form a volume that is dimensioned toclosely accommodate the dimensions of the static trial holder's prongs'cross-section. That is, as described below, the body of each prong isthicker than the semicircular extent that extends from the body, and assuch, whereas the semicircular extents fit into the annular groove, theprongs do not because their thickness is greater than the width of theannular groove opening. Each notch pair accommodates this greaterthickness, and as such, as the opposing semicircular extents of thestatic trial holder are placed into the annular groove, the bodies ofthe prongs of the static trial holder pass into the notches so that thesemicircular extents can continue into the annular groove and be seatedaround the cylindrical trunk. Once the prongs are fitted within thenotch pair, interference between the prongs and the notch walls limitsor prevents rotation of the static trial about a longitudinal axis(e.g., an axis parallel to the longitudinal axis of the cylindricaltrunk) with respect to the static trial holder.

With regard to features that can be used by the inserter/impactors, eachstatic trial (and each artificial intervertebral disc that the trialsapproximate) preferably includes an anteriorly facing flat surface,flanked by two anteriolaterally facing flat surfaces (one on each sideof the anteriorly facing flat surface), and, to provide for holding ofthe static trial or disc for an anterior insertion approach, a holespaced from the anteriorly facing flat surface, the hole having alongitudinal axis parallel to the anteriorly facing flat surface. Theholding pin of the inserter/impactor fits within the hole, and theangled flat surfaces of the static trial or disc fit against thecorrespondingly angled flat surfaces of the inserter/impactor, andoperation of the inserter/impactor pulls the holding pin toward the flatsurface of the inserter/impactor opposite the pin, to rigidly hold thestatic trial or disc by the baseplate.

In some embodiments of the inserter/impactor having a wedge plate, theholding pin protrudes from a wedge-shaped extended surface of the distalend of the inserter/impactor and is restricted from upward movement withrespect to the distal head by the presence of the wedge-shaped extendedsurface of the distal end of the inserter/impactor. More particularly,with any attempted upward movement of the holding pin, the pinencounters the upper surface of the channel in which the pin travels,preventing any such upward movement.) When the static trial orartificial disc is held in this manner, rotation of the static trial ordisc about a longitudinal axis (e.g., in the case of the trials, an axisparallel to the longitudinal axis of the cylindrical trunk) relative tothe inserter/impactor is prevented by interference of the corners of thestatic trial's or disc's flat surfaces and the corners of theinserter/impactor's flat surfaces, similar to the manner in which awrench holding a nut prevents rotation of the nut relative to thewrench. Further, the holding of the static trial or disc in this mannerallows for some repositioning of the static trial or disc in theintervertebral space via rotation of the static trial or disc in eitherdirection about the longitudinal axis of the intervertebral space.

Further, in some embodiments of the inserter/impactor having a wedgeplate, when the trial or disc is held in this manner, rotation of thetrial or disc about a lateral axis of the trial or disc relative to theinserter/impactor is prevented by interference of the inwardly facingsurface of the first baseplate (e.g., upper baseplate) of the trial ordisc and the corresponding surface (e.g., upper surface) of the wedge onthe distal end, and by interference of the inwardly facing surface ofthe second baseplate (e.g., lower baseplate) of the trial or disc andthe corresponding surface (e.g., lower surface) of the wedge on thedistal end. With regard to artificial discs, it is preferable that thewedge on the inserter/impactor will interfere between the first andsecond baseplates (e.g., upper and lower) so that the surfaces of thefirst and second baseplates align at a preferred 15 degrees angle oflordosis when the disc is held by the inserter/impactor.

Preferably, both of the baseplates of the static trial or disc havesimilarly configured flat surfaces, and both baseplates' flat surfacesfit against the angled flat surfaces of the inserter/impactor to providefor a more secure holding of the static trial or disc by theinserter/impactor. Also preferably, in order to provide for a holding ofthe static trial or disc for two additional (here, anteriolateral)insertion approaches, each static trial or disc also includes twoadditional holes, one spaced apart from one of the anteriolaterallyfacing flat surfaces, and the other spaced apart from the other of theanteriolaterally facing flat surfaces. Accordingly, operation of theinserter/impactor can fit the holding pin into either of these twoadditional holes, and hold the anteriolaterally facing flat surface (theone associated with the hole into which the pin is fit) of the statictrial or disc against the flat surface of the inserter/impactor oppositethe pin. It should be understood that preferably, in order to facilitatethese two additional approaches, the angle separating the anteriorlyfacing flat surface of the static trial or disc and one of theanteriolaterally facing flat surfaces of the static trial or disc isequal to the angle separating the anteriorly facing flat surface and theother of the anteriolaterally facing flat surfaces.

With regard to features that can be used by therepositioners/extractors, each static trial (and each artificialintervertebral disc that the trials approximate) preferably includes atleast two holes extending longitudinally into one of the baseplates ofthe trial or disc from the inwardly facing surface of the baseplate.More than two holes can be used to provide for multiplerepositioning/extracting approaches. Preferably, in order for the samerepositioning/extracting tool to be used for multiple approaches on thesame trial or artificial intervertebral disc, adjacent holes should beseparated by the same distance separating other adjacent holes.

As discussed in greater detail below with regard to therepositioners/extractors, in order to engage two of the holes, eachrepositioner/extractor has two pins extending in parallel from a centralshaft, perpendicular to the longitudinal axis of the central shaft. Thepins can be inserted into the holes, and pulling or pushing on thecentral shaft along its longitudinal axis when the holes are engagedpulls or pushes the static trial or artificial intervertebral disc inthe intervertebral space. Further, because two holes are engaged, thestatic trial or artificial intervertebral disc can be rotated in eitherdirection about a longitudinal axis passing through the intervertebralspace, by rotating of the central shaft of the repositioner/extractorabout its distal end, about an axis parallel to the longitudinal axes ofthe pins.

On each repositioner/extractor, the pins are formed on prongs thatextend laterally from the central shaft. The direction of the prongs,and the location of the pins relative to the central shaft, determinethe angle or angles of surgical approach for which a particularrepositioner/extractor can be used. Further, the number and location ofholes further determine the angle or angles of surgical approach forwhich a particular repositioner/extractor can be used. Accordingly, thepresent invention contemplates a variety of repositioner/extractors, anda variety of holes configurations, to provide the surgeon with a varietyof possible surgical approach angles.

As described in greater detail below, three repositioner/extractors areillustrated and described (symmetric, offset left, and offset right) forexample, and, for example, two hole configurations are illustrated anddescribed. A first hole configuration includes the hole configurationdescribed above, that is, three holes on one of the baseplates (e.g.,the lower baseplate), the holes being configured so that a first hole islocated in the anterior-posterior plane, and the adjacent (second andthird) holes are located in respective opposing anteriolateral planes oneither side of the first hole. A second hole configuration includes fourholes on one of the baseplates (e.g., the upper baseplate), the holesbeing configured so that first and second holes straddle theanterior-posterior plane, a third hole is located so that the third holeand the first hole straddle one of the opposing anteriolateral planes,and a fourth hole is located so that the fourth hole and the second holestraddle the other of the opposing anteriolateral planes.

With regard to the static trial holders described herein, the statictrial holders are provided primarily for use in holding, inserting,removing, and otherwise manipulating the static trials described herein.Preferably, the static trial holder has (in some embodiments, at an endof an extension of the static trial holder) a pair of opposing prongsthat open away from one another and close toward one another. Each ofthe prongs has a semicircular extent and the semicircular extents faceone another to define a circular holding enclosure that is useful forcapturing the cylindrical trunk of the static trial between them. Theprongs are spring biased toward a neutral position such that the holdingenclosure is spring biased to a receptive state in which the cylindricaltrunk can be snapped into (or out of) the holding enclosure bytemporarily placing the holding enclosure in an expanded state (byforcing the cylindrical trunk against the mouth of the enclosure) thatallows passage of the cylindrical trunk through the mouth of theenclosure.

Once the cylindrical trunk is in the enclosure, the holding enclosurecan be placed in a contracted state, or locked, where the trial is moresecurely held, so that the trial will not escape the holding enclosureas it is experiencing greater forces while being inserted and removedfrom the intervertebral space. This locking is effected by rotating asleeve that surrounds the prongs. The bore of the sleeve is configuredto press the prongs together when the sleeve is rotated a quarter turn(ninety degrees), and to allow them to separate when the sleeve is again(or in some embodiments, reverse) rotated a quarter turn (in eitherdirection). (In some embodiments, either quarter turn is in eitherdirection; e.g., in certain embodiments illustrated herein, the quarterturn that separates the prongs is a reverse rotation of the quarter turnthat presses them together). In some embodiments, the sleeve is biasedtoward stopping its rotation at either the “locked” or “unlocked” statesof the holding enclosure, by the cooperation of recesses on theextension's outer surface and corresponding spring plungers radiallydisposed to project from the sleeve's inner surface. In otherembodiments, the sleeve stops its rotation at either the “locked” or“unlocked” states of the holding enclosure, due to radially inwardlydirected screw heads on the sleeve's inner surface that ride inninety-degree arc grooves on the extension's outer surface and that stopwhen the end of the groove is reached.

Further, the sleeve of the static trial holder preferably has on itsexterior surface at least one stop protrusion that is positioned anddimensioned to extend dorsally or ventrally from the exterior surfacewhen the holding enclosure is in its “locked” state, so that when thesurgeon inserts the static trial into the intervertebral space, the stopprotrusions prevent the static trial from being inserted too far intothe space (that is, so that the stop protrusions hit against the lips ofthe adjacent vertebral body endplates before the static trial isinserted too far).

It should be understood that when a static trial is being held (eitherwhen the holding enclosure is in its receptive state or in itscontracted state), because the semicylindrical extents fit within theannular groove of the static trial, the static trial will not escapefrom the enclosure along the longitudinal axis of the cylindrical trunk.While the static trial holders are discussed herein as primarily usedfor manipulating the static trials, they are preferably is also usefulfor manipulating the distraction spacers described in the '127application, in that the semicircular extents of the pincers preferablyalso interact with the annular grooves and cylindrical trunks of thosedistraction spacers in the same manner as described herein.

With regard to the dynamic trial described herein, the dynamic trial isprovided primarily for distracting an intervertebral space according tothe procedures described herein and/or for determining the appropriatesize of an artificial intervertebral disc to be implanted (or whether aparticular size can be implanted) into the distracted intervertebralspace. While the distraction systems and methods described in the '127application are also useful for distracting an intervertebral space, thedynamic trial is provided as an additional or alternate distractiontool. Further, while the static trials described herein as useful fordetermining the appropriate size of an artificial intervertebral disc tobe implanted (or whether a particular size can be implanted), thedynamic trial is provided as an additional or alternate sizing tool.

The dynamic trial preferably includes a shaft having a bifurcated trialat a distal end. Each half of the bifurcated trial preferably has on itsoutwardly facing surface a convex dome that is shaped like the convexdome of the corresponding baseplate of the artificial intervertebraldisc that the dynamic trial approximates. The shaft includes an innershaft portion that centrally divides into upper and lower distalextensions that, from the point of division to their distal ends, areeach biased toward positions in which they converge toward one another.The lower distal extension is connected to the lower half of thebifurcated trial, and the upper distal extension is connected to theupper half of the bifurcated trial. Preferably, the upper half isadjustably connected to the upper distal extension by a pivot pin thatallows the upper half to rotate about a lateral axis that passes throughthe longitudinal and lateral center of the bifurcated trial. This axisof rotation allows the upper half, when separating from the lower half,to adjust to the orientation of the upper vertebral bone without causingthe bone to hinge relative to the lower vertebral bone. In order toeffect the separation of the upper and lower halves, the shaft furtherincludes an outer shaft potion that is translatable adjacent the innershaft portion, the outer shaft portion having a pin that passes betweenthe distal extensions.

The outer shaft portion is preferably translatable distally by theforward movement of a control knob near the proximal end of the shaft,and translatable proximally by backward movement of the control knob. Asthe outer shaft portion is pushed distally, the pin is pushed distallyto overcome the bias of the divided extensions to separate them andcorrespondingly separate the halves of the bifurcated trial. Preferably,markings are provided on the inner shaft portion to quantify the depth(to which the bifurcated trial has been expanded) corresponding to thedistance that the outer shaft portion has been translated with respectto the inner shaft portion. It is anticipated that the pushing forcerequired to separate the halves will increase as they separate, due tothe compression of the spine seeking to close the intervertebral spaceand the annulus seeking to prevent the adjacent vertebral discs fromseparating beyond a certain point. Therefore, to provide a mechanicaladvantage to the operator in the event that greater distraction isrequired, but the operator cannot push the control knob farther withunaided human effort, an fine control knob is provided. The fine controlknob is preferably threaded onto the proximal end of the inner shaftportion, proximal to the control knob. Thus, rotation of the finecontrol knob about the longitudinal axis of the inner shaft portion willcause the body of the fine control knob to press against the controlknob to move it farther distally. The interference of the threads of thefine control knob-inner shaft portion interface prevents the finecontrol knob from backing up proximally unless the fine control knob isreverse rotated to effect that result. Finally, the proximal end of theshaft is preferably flanged to serve as a slap hammer for impaction, ifnecessary for proper positioning of the bifurcated trial, and/or forcedextraction of the bifurcated trial.

With further regard to the inserter/impactors described herein, theinserter/impactors are provided primarily for holding, inserting,repositioning, removing, impacting, extracting, and otherwisemanipulating an artificial intervertebral disc (or static trial) havingfeatures suitable for being manipulated by the inserter/impactors.Exemplary suitable artificial intervertebral discs are described in the'032 and '327 patents with regard to FIGS. 8 a-z, 9 a-u, 10 a-u, 11 a-k,and 12 a-p thereof and by the accompanying descriptions therefor (e.g.,embodiments identified as the first, second, third, fourth, and fifthpreferred embodiments of the fourth embodiment family, etc.). Regardingthe features suitable for being manipulated by the inserter/impactors,such features include those discussed above as being suitable featureson the static trials and artificial intervertebral disc, namely, ananteriorly facing flat surface on the second (e.g., lower) baseplate ofthe trial or disc, flanked by two anteriolaterally facing flat surfaces(one on each side of the anteriorly facing flat surface), and, toprovide for holding of the trial or disc for an anterior insertionapproach, a hole spaced from the anteriorly facing flat surface, thehole having a longitudinal axis parallel to the anteriorly facing flatsurface.

The inserter/impactors include a shaft having a distal end that hasangled flat surfaces corresponding to and fittable against the angledflat surfaces of the static trial or artificial intervertebral disc, anda holding pin that extends from the center flat surface along alongitudinal axis of the shaft, the pin having a distal end that bendsdownward. The holding pin is spring loaded in a central channel of theshaft, so that it is biased toward and against a central flat surface(preferably, the bent end of the pin prevents it from entering thecentral channel). A flange, mechanically connected to the pin andtranslating adjacent the shaft, can be pushed distally to overcome thebias of the spring to space the pin away from the central flat surface.In this position, the pin can be inserted in the hole in the baseplateof the artificial intervertebral disc. Releasing the knob allows thespring to pull the pin back, causing the anteriorly facing surface ofthe baseplate to be held against the central flat surface of theinserter/impactor and the anteriolaterally facing flat surfaces of theartificial intervertebral disc to be held against the othercorresponding flat surfaces of the inserter/impactor. A knob on theinserter/impactor can be rotated about the longitudinal axis of theshaft to pull the pin tighter and lock its position to more securelyhold the baseplate, and reverse rotated to unlock and loosen the pin.(In some embodiments of the inserter/impactor having a wedge plate, theholding pin protrudes from a wedge-shaped extended surface of the distalend of the inserter/impactor and is restricted from upward movement withrespect to the distal head by the presence of the wedge-shaped extendedsurface of the distal end of the inserter/impactor. More particularly,with any attempted upward movement of the holding pin, the pinencounters the upper surface of the channel in which the pin travels,preventing any such upward movement.)

When the static trial or artificial intervertebral disc is held in thismanner, rotation of the trial or disc about its longitudinal axisrelative to the inserter/impactor is prevented by interference of thecorners of the trial's or disc's flat surfaces and the corners of theinserter/impactor's flat surfaces, similar to the manner in which awrench holding a nut prevents rotation of the nut relative to thewrench. Further, the holding of the trial or disc in this manner allowsfor some repositioning of the trial or disc in the intervertebral spacevia rotation of the trial or disc in either direction about thelongitudinal axis of the intervertebral space. Further, in someembodiments of the inserter/impactor having a wedge plate, when thetrial or disc is held in this manner, rotation of the trial or discabout a lateral axis of the trial or disc relative to theinserter/impactor is prevented by interference of the inwardly facingsurface of the first baseplate (e.g., upper baseplate) of the trial ordisc and the corresponding surface (e.g., upper surface) of the wedge onthe distal end, and by interference of the inwardly facing surface ofthe second baseplate (e.g., lower baseplate) of the trial or disc andthe corresponding surface (e.g., lower surface) of the wedge on thedistal end. With regard to artificial discs, it is preferable that thewedge on the inserter/impactor will interfere between the first andsecond baseplates (e.g., upper and lower) so that the surfaces of thefirst and second baseplates align at a preferred 15 degrees angle oflordosis when the disc is held by the inserter/impactor.

Preferably, both of the baseplates of the static trial or disc havesimilarly configured flat surfaces, and both baseplates' flat surfacesfit against the angled flat surfaces of the inserter/impactor to providefor a more secure holding of the static trial or disc by theinserter/impactor. Also preferably, in order to provide for a holding ofthe static trial or disc for two additional (here, anteriolateral)insertion approaches, each static trial or disc also includes twoadditional holes, one spaced apart from one of the anteriolaterallyfacing flat surfaces, and the other spaced apart from the other of theanteriolaterally facing flat surfaces. Accordingly, operation of theinserter/impactor can fit the holding pin into either of these twoadditional holes, and hold the anteriolaterally facing flat surface (theone associated with the hole into which the pin is fit) of the statictrial or disc against the flat surface of the inserter/impactor oppositethe pin. It should be understood that preferably, in order to facilitatethese two additional approaches, the angle separating the anteriorlyfacing flat surface of the static trial or disc and one of theanteriolaterally facing flat surfaces of the static trial or disc isequal to the angle separating the anteriorly facing flat surface and theother of the anteriolaterally facing flat surfaces.

Also preferably, as shown, the baseplates of each of the plurality ofstatic trials are appropriately lordotically angled relative to oneanother to ease insertion of the static trial into the intervertebralspace and to mimic how the artificial intervertebral disc will typicallybe oriented as it is being inserted. In some embodiments, theinserter/impactor holds the artificial intervertebral disc by the lowerbaseplate such that the upper baseplate is permitted to adjust itsdegree of lordosis relative to the lower baseplate during insertion, asdescribed in greater detail below. In other embodiments, theinserter/impactor holds the baseplates in a fixed degree of lordosisrelative to one another, as described in greater detail below.

With further regard to the repositioners/extractors described herein,each repositioner/extractor is provided primarily for repositioningand/or extracting a static trial or artificial intervertebral dischaving features suitable for being manipulated by therepositioner/extractor. Exemplary suitable artificial intervertebraldiscs are described in the '032 and '327 patents with regard to FIGS. 8a-z, 9 a-u, 10 a-u, 11 a-k, and 12 a-p thereof and by the accompanyingdescriptions therefor (e.g., embodiments identified as the first,second, third, fourth, and fifth preferred embodiments of the fourthembodiment family, etc.). Regarding the features suitable for beingmanipulated by each repositioner/extractor, such features include atleast two holes extending longitudinally into one of the baseplates ofthe static trial or artificial intervertebral disc from the inwardlyfacing surface of the baseplate. More than two holes can be used toprovide for multiple repositioning/extracting approaches. Preferably, inorder for the same repositioning/extracting tool to be used for multipleapproaches on the same trial or artificial intervertebral disc, adjacentholes should be separated by the same distance separating other adjacentholes.

In order to engage the two holes, each repositioner/extractor has twopins extending in parallel from a central shaft, perpendicular to thelongitudinal axis of the central shaft. The pins are spaced to engagethe two holes simultaneously, and each pin has a diameter smaller thanthe diameter of the hole it is to engage. Therefore, the pins can beinserted into the holes, and pulling or pushing on the central shaftalong its longitudinal axis when the holes are engaged pulls or pushesthe static trial or artificial intervertebral disc in the intervertebralspace. Further, because two holes are engaged, the static trial orartificial intervertebral disc can be rotated in either direction abouta longitudinal axis passing through the intervertebral space, byrotating of the central shaft of the repositioner/extractor about itsdistal end, about an axis parallel to the longitudinal axes of the pins.A handle at a proximal end of the central shaft is useful for pushing orpulling on the shaft. A flange adjacent the proximal end of the shaft isuseful for impaction (either with a distally directed force or aproximally directed force), if necessary to manipulate the shaft.

On each repositioner/extractor, the pins are formed on prongs thatextend laterally from the central shaft. The direction of the prongs,and the location of the pins relative to the central shaft, determinethe angle or angles of surgical approach for which a particularrepositioner/extractor can be used. Further, the number and location ofholes further determine the angle or angles of surgical approach forwhich a particular repositioner/extractor can be used. Accordingly, thepresent invention contemplates a variety of repositioner/extractors, anda variety of holes configurations, to provide the surgeon with a varietyof possible surgical approach angles.

With further regard to the leveler described herein, the leveler isprovided primarily for establishing a parallel orientation of thebaseplates (relative to one another), and/or securing the purchase ofthe stabilizing spikes, of an artificial intervertebral disc havingfeatures suitable for being manipulated by the leveler. Exemplarysuitable artificial intervertebral discs are described in the '032 and'327 patents with regard to FIGS. 8 a-z, 9 a-u, 10 a-u, 11 a-k, and 12a-p thereof and by the accompanying descriptions therefor (e.g.,embodiments identified as the first, second, third, fourth, and fifthpreferred embodiments of the fourth embodiment family, etc.). Regardingthe features suitable for being manipulated by the leveler, suchfeatures include suitably formed inwardly facing surfaces of thebaseplates of the artificial intervertebral disc.

More particularly, the leveler includes a shaft having a forked distalend formed by two opposing tongs that are symmetric to one another abouta longitudinal axis of the shaft. Each of the tongs has an extent thatinitially curves laterally outward away from the shaft and from theother tong's extent, to define a central pocket forward of the shaftbetween the tongs' extents. Each tong's extent then resumes a distaldirection to become parallel to the shaft and to the other tong'sextent.

Each tong's extent has an upper surface and a lower surface. The uppersurface is preferably shaped to conform against the inwardly facingsurface of a first (e.g., upper) baseplate of an artificialintervertebral disc, and the lower surface is preferably shaped toconform against the inwardly facing surface of a second (e.g., lower)baseplate of the artificial intervertebral disc, so that insertion ofthe forked distal end of the leveler between the baseplates, with thecentral pocket of the distal end avoiding the central portion of theartificial intervertebral disc, and with the upper and lower surfaces soengaging the inwardly facing surfaces of the baseplates, causes thebaseplates to be placed in parallel orientation with respect to oneanother. A handle is provided at a proximal end of the shaft forpushing, pulling, and otherwise manipulating the leveler as needed.

When the artificial intervertebral disc is inserted into theintervertebral space, its baseplates will typically be lordoticallyangled with respect to one another. The leveler can be applied to theartificial intervertebral disc to bring the baseplates parallel to oneanother. The forked distal end of the leveler is inserted so that thetongs' extents are placed between the inwardly facing surfaces of thebaseplates, and so that the central pocket of the leveler avoids thatportion of the artificial intervertebral disc that joins the baseplates.As the leveler is inserted, the tongs act as wedges to force theposterior portions of the baseplates away from one another. Accordingly,as the posterior portions are being separated, the stabilizing spikes onthe outwardly facing surfaces of the baseplates find or secure theirpurchase in the hard bone of the outer ring of the vertebral bodyendplates. When the forked distal end is fully seated, the extents ofthe tongs hold the baseplates parallel to one another, and so that thespikes are fully engaged in the endplates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-6 show front (FIG. 1), side (FIG. 2), perspective (FIG. 3), top(FIG. 4), bottom cutaway (FIG. 5) and top cutaway (FIG. 6) views of astatic trial of the present invention. FIGS. 7-12 show front (FIG. 7),side (FIG. 8), perspective (FIG. 9), top (FIG. 10), bottom cutaway (FIG.11), and top cutaway (FIG. 12) views of an alternate static trial of thepresent invention.

FIGS. 13-20 show front (FIG. 13), side cutaway (FIG. 14), top (FIG. 15),side cutaway (FIG. 16), bottom cutaway (FIG. 17), top cutaway (FIG. 18),bottom perspective (FIG. 19), and top perspective (FIG. 20) views of anexemplary artificial intervertebral disc of the present invention.

FIGS. 21-31 show top (FIG. 21), side (FIG. 22), perspective (FIG. 23),disassembly (FIGS. 24-30), and side cutaway (FIG. 31) views of a statictrial holder of the present invention.

FIGS. 32-34 and 44 show side (FIG. 32), top (FIG. 33), perspective (FIG.34), and side cutaway (FIG. 44) views of an alternate static trialholder 2000 of the present invention. FIGS. 35, 36, 37, and 38-39 show asleeve of the alternate static trial holder 2000 in side (FIG. 35), top(FIG. 36), side cutaway (FIG. 37), front (FIG. 38), and back (withpartial cutaway) (FIG. 39) views. FIGS. 40-42 show an extension of thealternate static trial holder 2000 in top (FIG. 40), proximal cutaway(FIG. 41), side (FIG. 42), and distal cutaway (FIG. 43) views.

FIGS. 45-47 show top (FIG. 45), side (FIG. 46), and perspective (FIG.47) views of the alternate static trial holder of FIGS. 32-44 holding analternate static trial of FIGS. 7-12 from an anterior approach hold.FIGS. 48-49 show top views of the alternate static trial holder of FIGS.32-44 holding an alternate static trial of FIGS. 7-12 from twoanterior-lateral approach holds.

FIG. 50 shows a perspective view of the alternate static trial holder ofFIGS. 32-44 holding an alternate static trial of FIGS. 7-12 from theanterior-lateral approach hold of FIG. 49.

FIGS. 51-54 show side (FIG. 51), top (FIG. 52), side cutaway (FIG. 53),and perspective (FIG. 54) views of a dynamic trial of the presentinvention.

FIGS. 55-58 show side (FIG. 55), top (FIG. 56), side cutaway (FIG. 57),and perspective (FIG. 58) views of an inserter/impactor of the presentinvention.

FIGS. 59-62 show side (FIG. 59), top (FIG. 60), side cutaway (FIG. 61),and perspective (FIG. 62) views of an inserter/impactor of the presentinvention holding a static trial of the present invention.

FIGS. 63-64 show top views of an inserter/impactor of the presentinvention holding a static trial of the present invention in twoalternative ways.

FIGS. 65-68 show side (FIG. 65), top (FIG. 66), side cutaway (FIG. 67),and perspective (FIG. 68) views of an inserter/impactor of the presentinvention holding an exemplary artificial intervertebral disc of thepresent invention.

FIGS. 69-70 show top views of an inserter/impactor of the presentinvention holding an exemplary artificial intervertebral disc of thepresent invention in two alternative ways.

FIGS. 71-73 show side (FIG. 71), perspective (FIG. 72), and close-upperspective (FIG. 73) views of a wedge plate inserter/impactor of thepresent invention.

FIGS. 74-77 show bottom (FIG. 74), side (FIG. 75), top (FIG. 76), andside cutaway (FIG. 77) views of a distal end of a wedge plateinserter/impactor of the present invention.

FIGS. 78-79 show top (FIG. 78) and side (FIG. 79) views of a wedge plateinserter/impactor of the present invention holding an exemplaryartificial intervertebral disc.

FIGS. 80-82 show top (FIG. 80), side (FIG. 81), and side cutaway (FIG.82) views of a distal end of a wedge plate inserter/impactor of thepresent invention holding an exemplary artificial intervertebral disc.

FIGS. 83-85 show side (FIG. 83), top (FIG. 84), and perspective (FIG.85) views of a symmetric repositioner/extractor of the presentinvention.

FIGS. 86-88 show side (FIG. 86), top (FIG. 87), and perspective (FIG.88) views of an offset left repositioner/extractor of the presentinvention.

FIGS. 89-91 show side (FIG. 89), top (FIG. 90), and perspective (FIG.91) views of an offset right repositioner/extractor of the presentinvention.

FIGS. 92-94 show side (FIG. 92), top (FIG. 93), and perspective (FIG.94) views of an alternative offset left repositioner/extractor of thepresent invention.

FIGS. 95-97 show side (FIG. 95), top (FIG. 96), and perspective (FIG.97) views of an alternative offset right repositioner/extractor of thepresent invention.

FIGS. 98-103 show exemplary various possible repositioner/extractorapproach angles with a three hole configuration of the presentinvention.

FIGS. 104-112 show exemplary various possible repositioner/extractorapproach angles with a four hole configuration of the present invention.

FIGS. 113-117 show bottom (FIG. 113), side (FIG. 114), front (FIG. 115),top partial perspective (FIG. 116), and bottom partial perspective (FIG.117) views of a leveler of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the invention will be described more fully hereinafter withreference to the accompanying drawings, it is to be understood at theoutset that persons skilled in the art may modify the invention hereindescribed while achieving the functions and results of the invention.Accordingly, the descriptions that follow are to be understood asillustrative and exemplary of specific structures, aspects and featureswithin the broad scope of the invention and not as limiting of suchbroad scope. Like numbers refer to similar features of like elementsthroughout.

Preferred embodiment of static trials of the present invention, and apreferred embodiment of an artificial intervertebral disc of the presentinvention, both for use with the instrumentation of the presentinvention, will now be described.

Referring now to FIGS. 1-6, a static trial of the present invention isshown in front (FIG. 1), side (FIG. 2), perspective (FIG. 3), top (FIG.4), bottom cutaway (FIG. 5) and top cutaway (FIG. 6) views. Referringnow to FIGS. 7-12, an alternate static trial of the present invention isshown in front (FIG. 7), side (FIG. 8), perspective (FIG. 9), top (FIG.10), bottom cutaway (FIG. 11) and top cutaway (FIG. 12) views. Referringnow to FIGS. 13-20, an artificial intervertebral disc of the presentinvention is shown in front (FIG. 13), side cutaway (FIG. 14), top (FIG.15), side cutaway (FIG. 16), bottom cutaway (FIG. 17), top cutaway (FIG.18), bottom perspective (FIG. 19), and top perspective (FIG. 20) views.

It should be understood that the illustration and reference herein tothe artificial intervertebral disc shown in FIGS. 13-20 is merely toshow an example of one type of artificial intervertebral disc that iscontemplated by, encompassed by, and suitable for use with, the presentinvention, and that such illustration and reference herein is not meantto limit the scope of the present invention or limit the uses of thepresent invention. Rather, any other artificial intervertebral disc (orany other orthopedic device) having suitable features for being usedwith the instrumentation and methods described herein are contemplatedby the present invention. Indeed, the features suitable for manipulation(e.g., the angled flat surfaces and adjacent holes and inwardly facingsurfaces) are encompassed by the present invention, regardless of towhat orthopedic device they may be applied. Other exemplary suitableartificial intervertebral discs include, but are not limited to, theartificial intervertebral discs described in the '032 and '327 patentswith regard to FIGS. 8 a-z, 9 a-u, 10 a-u, 11 a-k, and 12 a-p thereofand by the accompanying descriptions therefor (e.g., embodimentsidentified as the first, second, third, fourth, and fifth preferredembodiments of the fourth embodiment family, etc.). It should be notedthat, as can be seen from FIGS. 13-20, that the artificialintervertebral disc shown in FIGS. 13-20 has features similar to thoseof these other suitable artificial intervertebral discs of the '032 and'327 patents, and it should be understood that such similar features arestructurally and functionally as described in the '032 and '327 patents.Such similar features include an inwardly facing surface 164 a of theupper baseplate 164 a, and a convex structure 162 on the lower baseplate168 b, the convex structure 162 having an inwardly facing surface 164 b.

And, while the instrumentation described herein (e.g., the statictrials, static trial holders, dynamic trial, inserter/impactors,repositioners/extractors, and leveler) will be discussed for use withthe artificial intervertebral disc of FIGS. 13-20, such discussions aremerely by way of example and not intended to be limiting of their uses.Thus, it should be understood that the tools can be used with any of theartificial intervertebral discs disclosed in the '032 and '327 patents,or any other artificial intervertebral disc having (or being modifiableor modified to have) suitable features therefor. Moreover, it isanticipated that the features of the artificial intervertebral disc(e.g., the angled flat surfaces and accompanying holes and inwardlyfacing baseplate surfaces) and/or the static trials (e.g., thecylindrical trunks and angled flat surfaces and accompanying holesand/or engagement notches) that are used by the tools discussed hereinto hold and/or manipulate these devices (such features, it should benoted, were first shown and disclosed in the '182, '132, '081, '032 and'327 patents) can be applied, individually or collectively or in variouscombinations, to other trials, spacers, artificial intervertebral discsor other orthopedic devices as stand-alone innovative features forenabling such trials, spacers, artificial intervertebral discs, or otherorthopedic devices to be more efficiently and more effectively heldand/or manipulated by the tools described herein or by other toolshaving suitable features. In addition, it should be understood that theinvention encompasses artificial intervertebral discs, spacers, trials(static or dynamic), and/or other orthopedic devices, that have one ormore of the features disclosed herein, in any combination, and that theinvention is therefore not limited to artificial intervertebral discs,spacers, trials, and/or other orthopedic devices having all of thefeatures simultaneously.

Referring to FIGS. 1-6 and 7-12, a plurality of static trials 100,1000are provided primarily for use in determining the appropriate size of anartificial intervertebral disc to be implanted (or whether a particularsize of the artificial intervertebral disc can be implanted) into thedistracted intervertebral space (e.g., the artificial intervertebraldisc 160 of FIGS. 13-20). Preferably, for each artificial intervertebraldisc to be implanted, a plurality of sizes of the artificialintervertebral disc would be available. That is, preferably, a pluralityof the same type of artificial intervertebral disc would be available,each of the plurality having a respective width and depth dimensioncombination that allows it to fit within a correspondingly dimensionedintervertebral space. For example, the plurality of artificialintervertebral discs could include artificial intervertebral discshaving widths being either 35 mm or 40 mm, and depths ranging from 14 mmto 18 mm in 1 mm increments, for a total of 10 discs. Accordingly,preferably, each of the plurality of static trials 100,1000 for use witha particular plurality of differently sized artificial intervertebraldiscs would have a respective width and depth dimension setcorresponding to the width and depth of a respective one of theplurality of differently sized artificial intervertebral discs. Forexample, the plurality of static trials 100,1000 for use with the set ofartificial intervertebral discs described for example could includestatic trials having widths being either 35 mm or 40 mm, and depthsranging from 14 mm to 18 mm in 1 mm increments, for a total of 10 statictrials. It should be understood that the artificial intervertebral discsand/or the static trials 100,1000 can be offered in a variety ofdimensions without departing from the scope of the invention, and thatthe dimensions specifically identified and quantified herein are merelyexemplary. Moreover, it should be understood that the set of statictrials 100,1000 need not include the same number of trials for eachartificial intervertebral disc in the set of artificial intervertebraldiscs, but rather, none, one, or more than one trial can be included inthe trial set for any particular artificial intervertebral disc in theset.

Each of the static trials 100,1000 shown is exemplary for all of thestatic trials in the plurality of static trials; preferably the statictrials in the plurality differ from one another only with regard tooverall dimensions as described above) includes at least one featurethat can be engaged by a tool. Suitable tools include, but are notlimited to, the static trial holders described below, theinserter/impactors described below, and the repositioners/extractorsdescribed below.

Specifically, the static trial 100,1000 includes a recess 102,1020 thatcan be engaged by the opposing semicircular extents 216 a-b,2160 a-b ofthe static trial holder 200,2000. Preferably, this recess 102,1020 formsan annular groove 104,1040 that establishes a cylindrical trunk 106,1060between the upper and lower baseplates 108 a-b,1080 a-b of the statictrial 100,1000, such that the baseplates 108 a-b,1080 a-b extend asflanges 110 a-b,110 a-b from either end of the cylindrical trunk106,1060. Accordingly, preferably, the opposing semicircular extents 216a-b,2160 a-b each have a thickness smaller than the width of the annulargroove 104,1040, and as such fit into the annular groove 104,1040 togrip the cylindrical trunk 106,1060 between them. (Importantly, withregard to the alternate static trials 1000 being engaged by thealternate static trial holder 2000, as discussed in greater detailbelow, the body of the prongs 2140 a-b (from which the semicircularextents 2160 a-b extend) has a thickness greater than the width of theannular groove 1040 (and as such does not fit within the annular groove)but small enough to be accommodated by the opposing notches 1320 a-b ofthe alternate static trial 1000 as described below.)

In some embodiments, while not shown in FIGS. 1-6 or FIGS. 7-12, it isalso preferable that the annular groove 104,1040 radially widenoutwardly, such that the walls 112,1120 of the annular groove 104,1040are tapered toward one another with the increasing depth of the groove104,1040, such that the floor 114,1140 of the groove 104,1040 is morenarrow than the opening 116,1160 of the groove 104,1040. Accordingly,preferably, in such embodiments, each semicircular extent 216 a-b,2160a-b correspondingly radially widens outwardly, such that the thinnerportion of the extent 216 a-b,2160 a-b fits closer to the floor 114,1140of the annular groove 104,1040, so that the tapered surfaces of theextents 216 a-b,2160 a-b compress against the tapered walls 112,1120 ofthe annular groove 104,1040 when the static trial 100,1000 is engaged bythe static trial holder 200,2000. This taper locking provides for asecure grip so that the static trial 100,1000 can be manipulatedaccurately and efficiently.

In some embodiments, while not shown in FIGS. 1-6 or FIGS. 7-12, it isalso preferable that the floor of the annular groove 104,1040 of thecylindrical trunk 106,1060 be ridged (e.g., have ridges that runparallel to the longitudinal axis of the cylindrical trunk), and thesurfaces of the semicircular extents 216 a-b,2160 a-b of the statictrial holder 200,2000 that compress against the floor of the annulargroove 104,1040 when the static trial holder 200,2000 grips the statictrial 100,1000 be correspondingly provided with ridges. The interlockingof the ridges of the static trial 100,1000 with the ridges of the statictrial holder 200,2000 when the static trial 100,1000 is engaged preventsrotation of the static trial 100,1000 about the longitudinal axis of thecylindrical trunk 106,1060 with respect to the static trial holder200,2000.

Preferably, as shown in FIGS. 7-12, each alternate static trial 1000includes (on any alternate static trial surface that faces the desiredengagement approach direction of the alternate static trial holder 2000)opposing recesses, preferably formed as upper and lower notches, anupper notch in the upper baseplate and a lower notch in the lowerbaseplate. For example, opposing notches 1320 b and 1320 e are on eachof the anteriorly facing flat surfaces of the upper 1080 a and lower1080 b baseplates. And, for example, opposing notches 1320 a and 1320 dare on one of the anterior-laterally facing flat surfaces of the upper1080 a and lower 1080 b baseplates. And, for example, opposing notches1320 c and 1320 f are on the other of the anterior-laterally facing flatsurfaces of the upper 1080 a and lower 1080 b baseplates. Preferably,the notches 1320 a-f are sized so that the opposing notches of each pair(1320 a,d, 1320 b,e, and 1320 c,f) form a volume that closelyaccommodates the dimensions of the alternate static trial holder's 2000prongs' 2140 a-b cross-section. That is, as described below, the body ofeach prong 2140 a-b is thicker than the semicircular extent 2160 a-bthat extends from the body, and as such, whereas the semicircularextents 2160 a-b fit into the annular groove 1040, the prongs 2140 a-bdo not because the depth 2260 of their cross-section (described below)is greater than the width of the annular groove opening 1160. However,each notch pair (1320 a,d, 1320 b,e, and 1320 c,f) accommodates thisgreater thickness, in that each notch 1320 a-f has a depth 1340, and,when the two notch depths 1340 of the opposing notches of the notch pairare taken together with the width of the annular groove 1040, thecombined distance accommodates the depth 2260 of the static trialholder's 2000 prongs' 2140 a-b cross-section. Further, each notch 1320a-f has a width 1360 that accommodates the width 2240 of the alternatestatic trial holder's 2000 prongs' 2140 a-b cross-section. (It should benoted that the width 1360 accommodates the width 2240 of the alternatestatic trial holder's 2000 prongs' 2140 a-b cross-section even when theprongs 2140 a-b are separated to place the holding enclosure 2100 in anexpanded state as described below. This enables the notches 1320 a-f toaccommodate the width 2240 of the prongs' cross-section as thecylindrical trunk 1060 of the static trial 1000 is being snapped intothe holding enclosure 2100 as described below.) As such, as the opposingsemicircular extents 2160 a-b of the alternate static trial holder 2000are placed into the annular groove 1040, the bodies of the prongs 2140a-b pass into the notches of the pair so that the semicircular extents2160 a-b can continue into the annular groove 1040 and be seated aroundthe cylindrical trunk 1060. More specifically, the prongs 2140 a-b ofthe alternate static trial holder 2000 fit into the notches above andbelow it (e.g., 1320 b and 1320 e for an anterior approach; 1320 a and1320 d for an anterior-lateral approach; and 1320 c and 1320 f foranother anterior-lateral approach). Once the prongs 2140 a-b are fittedwithin the notch pair, interference between the prongs 2140 a-b and thenotch walls limits or prevents rotation of the alternate static trial1000 about a longitudinal axis (e.g., an axis parallel to thelongitudinal axis of the cylindrical trunk 1060) with respect to thealternate static trial holder 2000.

It should be understood that configurations having more or fewernotches, and in a variety of locations, are contemplated by theinvention, and the detailed descriptions of only one type of notchconfiguration is not meant to limit the invention to only thisconfiguration. Importantly, the invention encompasses using a singlenotch in a baseplate, a single notch pair, or any number of notches ornotch pairs, formed in any suitable manner with any suitable dimensions,in any number of locations on a spacer, a trial or an artificialintervertebral disc (not limited to locations on the baseplates), forpurposes of enabling the spacer, trial, or disc to be engaged by amanipulation instrument (not limited to a static trial holder) thatengages the notch, for the purpose of limiting rotation of the spacer,trial, or disc (or other orthopedic implant) with respect to theinstrument or for any other purpose, and/or to enable the surgeon towork from a variety of approaches. For example, the notch configurationdescribed herein, in cooperation with the alternate static trial holder,provides the surgeon with the ability to work from a directly anteriorapproach, as well as two anteriolateral approaches. It should beunderstood that additional notch configurations can enable the surgeonto work from a directly posterior approach, posteriolateral approaches,directly lateral approaches, or anteriolateral approaches that aredifferent than those illustrated. For example, the placement of one ormore suitably spaced notches (or the addition of one or more notches) onthe posterior edge, and/or one or both of the lateral edges of one orboth of the baseplates, would enable the surgeon to use the alternatestatic trial holder of the present invention to achieve such approaches.

Additionally with regard to features that can be engaged by a tool, eachof the static trials 100,1000 includes at least one feature that can beengaged by a tool that preferably is also used to engage the artificialintervertebral disc that the trial approximates. Suitable tools that canengage both the trials and the artificial intervertebral disc include,but are not limited to, the inserter/impactors described below.Specifically, for being engaged by the inserter/impactors 400,4000, eachstatic trial 100,1000 and artificial intervertebral disc 160 includes ananteriorly facing flat surface 120 b,1200 b,180 b, flanked by twoanteriolaterally facing flat surfaces 120 a,1200 a,180 a and 120 c,1200c,180 c (one on each side of the anteriorly facing flat surface 120b,1200 b,180 b), and, to provide for holding of the static trial100,1000 or disc 160 for an anterior insertion approach, a hole 122b,1220 b,182 b spaced from the anteriorly facing flat surface 120 b,1200b,180 b, the hole 122 b,1220 b,182 b having a longitudinal axis parallelto the anteriorly facing flat surface 120 b,1200 b,180 b.

The holding pin 408,4080 of the inserter/impactor 400,4000 fits withinthe hole 122 b,1220 b,182 b, and the angled flat surfaces 120 a-c,1200a-c,180 a-c of the static trial 100,1000 or disc 160 fit against thecorrespondingly angled flat surfaces 420 a-c,4200 a-c of theinserter/impactor 400,4000, and operation of the inserter/impactor400,4000 pulls the holding pin 408,4080 toward the flat surface 120b,1200 b,180 b of the inserter/impactor 400,4000 opposite the pin408,4080, to rigidly hold the static trial 100,1000 or disc 160 by thestructure of the static trial 100,1000 or disc 160 having the hole 122b,1220 b,182 b (e.g., the baseplate 108 b,1080 b,168 b).

When the static trial 100,1000 or disc 160 is held in this manner,rotation of the static trial 100,1000 or disc 160 about a longitudinalaxis (of the static trial 100,1000 or disc 160) relative to theinserter/impactor 400,4000 is prevented by interference of the cornersof the static trial's 100,1000 or disc's 160 flat surfaces 120 a-c,1200a-c,180 a-c and the corners of the inserter/impactor's 400,4000 flatsurfaces 420 a-c,4200 a-c, similar to the manner in which a wrenchholding a nut prevents rotation of the nut relative to the wrench.Further, the holding of the static trial 100,1000 or disc 160 in thismanner allows for some repositioning of the static trial 100,1000 ordisc 160 in the intervertebral space via rotation of the static trial100,1000 or disc 160 in either direction about the longitudinal axis ofthe intervertebral space.

Further, with regard to the wedge plate inserter/impactor 4000, when thestatic trial 100,1000 or disc 160 is held in this manner, rotation ofthe static trial 100,1000 or disc 160 about a lateral axis (of thestatic trial 100,1000 or disc 160) relative to the inserter/impactor4000 is prevented by interference of the inwardly facing surface (e.g.,164 a) of the first baseplate (e.g., upper baseplate) of the statictrial 100,1000 or disc 160 and the upper surface 4200 g of the wedge onthe distal end 4040, and by interference of the inwardly facing surface(e.g., 164 b) of the second baseplate (e.g., lower baseplate) of thestatic trial 100,1000 or disc 160 and the lower surface 4200 h of thewedge on the distal end 4040. Accordingly, the holding of the statictrial 100,1000 or disc 160 in this manner allows for some repositioningof the static trial 100,1000 or disc 160 in the intervertebral space viarotation of the static trial 100,1000 or disc 160 in either directionabout the longitudinal or latitudinal axis of the intervertebral space.

Preferably, both of the baseplates of the static trial 100,1000 or disc160 have similarly configured flat surfaces. For example, the lowerbaseplate's 108 b,1080 b,168 b flat surfaces 120 a-c,1200 a-c,180 a-chave similarly configured and similarly oriented counterpart flatsurfaces 120 d-f,1200 d-f,180 d-f on the upper baseplate 108 a,1080a,168 a. Further preferably, both baseplates' 108 a-b,1080 a,168 a-bflat surfaces 120 a-f,1200 a-f,180 a-f face the angled flat surfaces 420a-c,4200 a-f of the inserter/impactor 400,4000 when the static trial100,1000 or disc 160 is held by the inserter/impactor 400,4000. Forexample, in an anterior approach for the trial 100,1000 (as shown inFIGS. 59-62, showing the trial 100 being held by the inserter/impactor400 as an example for of how either trial 100,1000 can be held by eitherinserter/impactor 400,4000), 120 a,1200 a and 120 d,1200 d facing 420 a(or 4200 a and 4200 d), 120 b,1200 b and 120 e,1200 e facing 420 b (or4200 b and 4200 e), and 120 c,1200 c and 120 f,1200 f facing 420 c (or4200 c and 4200 f), and in an anterior approach for the disc 160 (asshown in FIGS. 65-68, showing the disc 160 being held by theinserter/impactor 400 as an example for of how the disc 160 can be heldby either inserter/impactor 400,4000), 180 a and 180 d facing 420 a (or4200 a and 4200 d), 180 b and 180 e facing 420 b (or 4200 b and 4200 e),and 180 c and 180 f facing 420 c (or 4200 c and 4200 f).

It should be noted that preferably, when the static trial 100,1000 isheld by the inserter/impactor 400,4000, the flat surfaces 120 a-c,1200a-c and the counterpart flat surfaces 120 d-f,1200 d-f are tightly heldagainst the angled flat surfaces 420 a-c,4200 a-f of theinserter/impactor 400,4000 as described above. It is also preferablethat the baseplates 108 a-b,1080 a-b of each of the plurality of statictrials 100,1000 be appropriately lordotically angled relative to oneanother to ease insertion of the static trial 100,1000 into theintervertebral space and to mimic how the artificial intervertebral disc160 will typically be oriented as it is being inserted using theinserter/impactor 400,4000. While not shown in FIGS. 1-6 or FIGS. 7-12,in some embodiments, when the static trials 100,1000 are formed in sucha lordotically oriented configuration, it is preferable that the flatsurfaces 120 d-f,1200 d-f on the first (e.g., upper) baseplate 108a,1080 a be parallel to the flat surfaces 120 a-c,1200 a-c of the second(e.g., lower) baseplate 108 b,1080 b in the static trial's 100,1000appropriately lordotically oriented configuration, so that when thestatic trial 100,1000 is held tightly by the inserter/impactor 400,4000,the flat surfaces 120 a-f,1200 a-f are flush with the flat surfaces 420a-c,4200 a-f of the inserter/impactor 400,4000 even though thebaseplates 108 a-b,1080 a-b are lordotically angled with respect to oneanother.

With regard to the inserter/impactor 400, by contrast, preferably, whenthe artificial intervertebral disc 160 is held by the inserter/impactor400, the flat surfaces 180 a-c are tightly held against the angled flatsurfaces 420 a-c of the inserter/impactor 400 as described above, butthe counterpart flat surfaces 180 d-f are loosely held against theangled flat surfaces 420 a-c of the inserter/impactor 400. As such, thestructure of the artificial intervertebral disc 160 having thecounterpart flat surfaces 180 d-f (e.g., the upper baseplate 168 a) isable to angulate and rotate to a limited extent relative to thestructure of the artificial intervertebral disc 160 having the flatsurfaces 180 a-c. This permits the artificial intervertebral disc 160 toadjust to the intervertebral space (e.g., to the angulation of theadjacent vertebral endplates, defining the intervertebral space,relative to one another) as it is being inserted thereinto. That is,typically, the adjacent vertebral endplates will be lordotically angledwith respect to one another as a result of the intervertebral spacebeing prepared and distracted. As the artificial intervertebral disc 160is then inserted into the intervertebral space using theinserter/impactor 400, then, the baseplates 168 a-b will be permitted tolordotically angle with respect to one another to squeeze into theintervertebral space.

With regard to the wedge plate inserter/impactor 4000, when theartificial intervertebral disc 160 is held by the inserter/impactor4000, the wedge surfaces of the distal end 4040 protrude from a distancemidway with respect to the top and bottom of the distal end 4040 andspan (e.g., right to left or vice-versa) the entire distal face of thedistal end 4040, and the surfaces 4200 d-f above the wedge on the distalend 4040 are respectively perpendicular to the wedge's upper surface4200 g such that each is disposed in parallel with its respectivecorresponding surface of the disc 160 when the disc 160 is held by theinserter/impactor 4000 at the appropriate lordosis angle. (And,accordingly, are angled approximately 15 degrees with respect to thesurfaces below the wedge 4200 a-c.)

Preferably, for an anterior approach, the wedge-shaped extension 4042 isdesigned and shaped to fit with its antero-lateral confronting surfaces(4200 d,f and 4200 a,c) tightly against the correspondinglyantero-laterally facing surfaces (180 d,f and 180 a,c) of the disc 160,but such that its anterior confronting surfaces (4200 e and 4200 b) areslightly spaced from the anteriorly facing surfaces (180 d and 180 b) ofthe disc 160, when the disc is held by the inserter/impactor 4000. Thisis primarily to address manufacturing issues (in some instances,tolerances may not be adequately defined to ensure that all of thosesurfaces fit tightly against their corresponding surfaces), so that ifthere are manufacturing anomalies, any slight tolerance differences thatmay exist are nevertheless still adequate to ensure at least the tightfitting of the antero-lateral confronting surfaces, so that manipulationof the disc 160 is possible (e.g., in the manner of a wrench against anangled nut). This can be achieved, e.g., by designing the anteriorconfronting surfaces (4200 e and 4200 b) to each be slightly greater inlength than the corresponding anteriorly facing surfaces (180 e and 180b) of the disc baseplates, while still being angled with respect to theantero-lateral confronting surfaces (4200 d,f and 4200 a,c) at the sameangle the antero-laterally facing surfaces (180 d,f and 180 a,c) of thedisc baseplates are angled with respect to the anteriorly facingsurfaces (180 e and 180 b) of the disc. The increased length of theanterior confronting surfaces on the wedge extension results in theslight clearance between the anteriorly facing surfaces (180 e and 180b) of the disc and the corresponding anterior confronting surface (4200e and 4200 b) of the wedged distal end, thereby ensuring that the discwill be fully seated against the antero-lateral confronting surfaces ofthe distal end despite possible manufacturing, material or otherinevitable variations in tolerances of the artificial intervertebraldisc or the inserter/impactor. As noted above, similar in this regard tothe manner in which a wrench engages a nut, this fitting increases themechanical advantage toward repositioning the disc in the intervertebralspace. It should be noted, inasmuch as the inserter/impactor 4000described herein can engage the disc from the antero-lateral angles aswell, the anterior confronting surfaces (4200 e and 4200 b) should alsobe longer than the antero-laterally facing surfaces (180 d,f and 180a,c) of the disc, so that a similar fitting occurs when the disc is heldfrom the antero-lateral angles. Stated broadly, the primary confrontingsurfaces (e.g., the anterior confronting surfaces) of theinserter/impactor are preferably slightly longer than the primaryconfronted surfaces (e.g., anteriorly facing surfaces) of the disc forany given holding orientation.

In order to provide for a holding of the static trial 100,1000 or disc160 for two additional (here, anteriolateral) insertion approaches, eachstatic trial 100,1000 or disc 160 also preferably includes twoadditional holes 122 a,1220 a,182 a and 122 c,1220 c,182 c, one (e.g.,122 a,1220 a,182 a) spaced apart from one of the anteriolaterally facingflat surfaces (e.g., 120 a,1200 a,180 a), and the other (e.g., 122c,1220 c,182 c) spaced apart from the other of the anteriolaterallyfacing flat surfaces (e.g., 120 c,1200 c,180 c). Accordingly, operationof the inserter/impactor 400,4000 can fit the holding pin 408,4080 intoeither of these two additional holes 122 a,1220 a,182 a or 122 c,1220c,182 c, and hold the associated anteriolaterally facing flat surface(the one associated with the hole into which the pin 408,4080 is fit) ofthe static trial 100,1000 or disc 160 against the flat surface of theinserter/impactor 400,4000 opposite the pin 408,4080. For example, in afirst anteriolateral approach for the trial 100,1000 (as shown in FIG.63 as an example of how either trial 100,1000 can be engaged by eitherinserter/impactor 400,4000), 120 a,1200 a and 120 d,1200 d notconfronted, 120 b,1200 b and 120 e,1200 e facing 420 a (or 4200 a and4200 d), and 120 c,1200 c and 120 f,1200 f facing 420 b (or 4200 b and4200 e), and a first anteriolateral approach for the disc 160 (as shownin FIG. 69 as an example of the how the disc 160 can be engaged byeither inserter/impactor 400,4000), 180 a and 180 d not confronted, 180b and 180 e facing 420 a (or 4200 a and 4200 d), and 180 c and 180 ffacing 420 b (or 4200 b and 4200 e). And, for example, in a secondanteriolateral approach for the trial 100 (as shown in FIG. 64 as anexample of how either trial 100,1000 can be engaged by eitherinserter/impactor 400,4000), 120 a,1200 a and 120 d,1200 d facing 420 b(or 4200 b and 4200 e), 120 b,1200 b and 120 e,1200 e facing 420 c (or4200 c and 4200 f), and 120 c,1200 c and 120 f,1200 f not confronted,and a second anteriolateral approach for the disc 160 (as shown in FIG.70 as an example of how the disc 160 can be engaged by eitherinserter/impactor 400,4000), 180 a and 180 d facing 420 b (or 4200 b and4200 e), 180 b and 180 e facing 420 c (or 4200 c and 4200 f), and 180 cand 180 f not confronted.

It should be understood that preferably, in order to facilitate theseadditional approaches, the angle separating the anteriorly facing flatsurface of the static trial 100,1000 or disc 160 and one of theanteriolaterally facing flat surfaces of the static trial 100,1000 ordisc 160 is equal to the angle separating the anteriorly facing flatsurface and the other of the anteriolaterally facing flat surfaces.Preferably, the surfaces are angled with respect to one another at anangle of 33.4 degrees.

It should also be understood that the inclusion of additional adjacentangulated surfaces and/or additional notches (or placing the angulatedsurfaces or notches in other locations on the trial or disc), and/orincluding corresponding holes adjacent to such angulated surfaces ornotches, can provide the surgeon with additional approaches, e.g., otheranteriolateral approaches, directly lateral approaches, posteriolateralapproaches, and/or directly posterior approaches. For example, a trialor disc can have angled surfaces (and corresponding holes) along theentire perimeter of one or both of the baseplates, and thus enable thesurgeon to engage the trial or disc from a number of angles, includinganterior, posterior, lateral, anteriolateral, and posteriolateralangles. Or, for example, a trial (or disc) can have notches located ondirectly laterally facing surfaces or posterior surfaces orposterior-laterally facing surfaces, and thus enable the surgeon toengage the trial (or disc) with a static trial holder from a number ofangles, including anterior, posterior, lateral, anteriolateral, andposteriolateral angles. (It should be noted that, while the opposingnotches of the alternate static trials are shown formed in conjunctionwith the angulated surfaces of the baseplates, neither the number northe placement of the opposing notches need coincide or be related to thenumber or placement of the angulated surfaces of the baseplates. Forexample, the notches can be applied to a trial or disc having curvedapproach surfaces.)

Additionally with regard to features that can be engaged by a tool, eachof the static trials 100,1000 includes at least one feature that can beengaged by a tool that preferably is also used to engage the artificialintervertebral disc that the trial approximates. Suitable tools that canengage both the trial and the artificial intervertebral disc include,but are not limited to, the repositioners/extractors 500,510,520,530,540described below. Specifically, for being engaged by therepositioners/extractors, each static trial 100,1000 and artificialintervertebral disc 160 includes at least two holes extendinglongitudinally into one of the baseplates of the static trial 100,1000or artificial intervertebral disc 160 from the inwardly facing surfaceof the baseplate. More than two holes can be used to provide formultiple repositioning/extracting approaches. Preferably, in order forthe same repositioning/extracting tool to be used for multipleapproaches on the same trial or artificial intervertebral disc, adjacentholes should be separated by the same distance separating other adjacentholes.

As discussed in greater detail below with regard to therepositioners/extractors 500,510,520,530,540, in order to engage two ofthe holes, each repositioner/extractor has two pins extending inparallel from a central shaft, perpendicular to the longitudinal axis ofthe central shaft. The pins are spaced to engage the two holessimultaneously, and each pin has a diameter smaller than the diameter ofthe hole it is to engage. Therefore, the pins can be inserted into theholes, and pulling or pushing on the central shaft along itslongitudinal axis when the holes are engaged pulls or pushes the statictrial or artificial intervertebral disc in the intervertebral space.Further, because two holes are engaged, the static trial or artificialintervertebral disc can be rotated in either direction about alongitudinal axis passing through the intervertebral space, by rotatingthe central shaft of the repositioner/extractor about its distal end,about an axis parallel to the longitudinal axes of the pins. A handle ata proximal end of the central shaft is useful for pushing or pulling onthe shaft. A flange adjacent the proximal end of the shaft is useful forimpaction (either with a distally directed force or a proximallydirected force), if necessary to manipulate the shaft.

On each repositioner/extractor, the pins are formed on prongs thatextend laterally from the central shaft. The direction of the prongs,and the location of the pins relative to the central shaft, determinethe angle or angles of surgical approach for which a particularrepositioner/extractor can be used. Further, the number and location ofholes further determine the angle or angles of surgical approach forwhich a particular repositioner/extractor can be used. Accordingly, thepresent invention contemplates a variety of repositioner/extractors, anda variety of holes configurations, to provide the surgeon with a varietyof possible surgical approach angles.

As described in greater detail below, three repositioner/extractors areillustrated and described (symmetric, offset left, and offset right) forexample, and, for example, two hole configurations are illustrated anddescribed. Referring again to FIGS. 1-20 and FIGS. 7-12, a first holeconfiguration includes the hole configuration described above, that is,three holes on one of the baseplates (e.g., the lower baseplate 108b,1080 b,168 b), the holes being configured so that a first hole 122b,1220 b,182 b is located in the anterior-posterior plane, and theadjacent (second 122 a,1220 a,182 a and third 122 c,1220 c,182 c) holesare located in respective opposing anteriolateral planes on either sideof the first hole 122 b,1220 b,182 b. (This hole configuration is alsoshown in FIGS. 98-103, each of which shows a top cutaway view of theartificial intervertebral disc 160 of FIGS. 13-20, showing its lowerbaseplate 168 b, having the first hole configuration, engaged by one ofthe repositioners/extractors 500,510,520. Each view of the lowerbaseplate 168 b shows the first hole 182 b, the second hole 182 a, andthe third hole 182 c of the first hole configuration.)

Referring again to FIGS. 1-20, a second hole configuration includes fourholes on one of the baseplates (e.g., the upper baseplate 108 a,168 a),the holes being configured so that first (e.g., 130 c,190 c) and second(e.g., 130 b,190 b) holes straddle the anterior-posterior plane, a thirdhole (e.g., 130 d,190 d) is located so that the third hole and the firsthole straddle one of the opposing anteriolateral planes, and a fourthhole (e.g., 130 a,190 a) is located so that the fourth hole and thesecond hole straddle the other of the opposing anteriolateral planes.While this second hole configuration is not illustrated with regard tothe static trials 1000, it should be understood that the static trials1000 can be configured with such second hole configuration, or any otherhole configuration, without departing from the scope of the presentinvention. (It should be noted that, while the opposing notches of thestatic trials 1000 are shown formed in conjunction with the holes in thebaseplates, neither the number nor the placement of the opposing notchesneed coincide or be related to the number or placement of the holes inthe baseplates.) (This second hole configuration is also shown in FIGS.104-112, each of which shows a bottom cutaway view of the artificialintervertebral disc of FIGS. 1-20, showing its upper baseplate 168 a,having the second hole configuration, engaged by one of therepositioners/extractors 500,510,520. Each view of the upper baseplateshows the first hole 190 c, the second hole 190 b, the third hole 190 d,and the fourth hole 190 a, of the second hole configuration.)

It should be understood that configurations having more or fewer holes,and in a variety of locations, are contemplated by the invention, andthe detailed descriptions of only two hole configurations is not meantto limit the invention to only these two configurations. Importantly,the invention encompasses using a hole or any number of holes, bored atany suitable angle, whether parallel to other holes or not, in anynumber of locations on a spacer, a trial or an artificial intervertebraldisc (not limited to locations on the baseplates), for purposes ofenabling the spacer, trial, or disc to be engaged by a manipulationinstrument (not limited to a repositioner/extractor) that engages thehole, and/or to enable the surgeon to work from a variety of approaches.For example, as described in more detail below, the first and secondhole configurations described herein, in cooperation with therepositioner/extractors, provide the surgeon with the ability to workfrom a directly anterior approach, as well as several anteriolateralapproaches. It should be understood that additional hole configurationscan enable the surgeon to work from a directly posterior approach,posteriolateral approaches, directly lateral approaches, oranteriolateral approaches that are different that those illustrated. Forexample, the placement of one or more suitably spaced holes (or theaddition of one or more holes) on the posterior edge, and/or one or bothof the lateral edges of one or both of the baseplates, would enable thesurgeon to use the repositioner/extractors of the present invention toachieve such approaches.

Thus, it can be seen that each of the repositioner/extractors can beused in more than one manner depending on the tool desired and theapproach desired. These manners are described in greater detail belowand illustrated in FIGS. 98-112 with regard to the detailed descriptionof the repositioners/extractors.

Also preferably, the baseplates 108 a-b,1080 a-b of each of theplurality of static trials 100,1000 preferably has a convex dome 124a-b,1240 a-b on its outwardly facing surface 126 a-b,1260 a-b that isshaped like the convex dome 184 a-b on the outwardly facing surface 186a-b of the corresponding baseplate 168 a-b of the artificialintervertebral disc 160 that the static trial 100,1000 approximates.Preferably, each convex dome 124 a-b,1240 a-b is smooth, rather thanhaving a porous coating that is preferred for the convex domes 184 a-bof the artificial intervertebral disc 160, and each outwardly facingsurface 126 a-b,1260 a-b does not have stabilizing spikes such as thestabilizing spikes 188 a-b on the outwardly facing surfaces 186 a-b ofthe artificial intervertebral disc 160. The omission of these devicestabilizing and bone ingrowth encouraging structures and surfaces on thestatic trials 100,1000 enables the surgeon to test the size of theartificial intervertebral disc 160 to be implanted without traumaticallyengaging the vertebral body endplates.

Accordingly, the surgeon can prepare and distract the intervertebralspace, and then insert and remove at least one of the static trials (ormore, as necessary) to find the size that is most appropriate for theintervertebral space.

Preferred embodiments of static trial holders of the present inventionwill now be described.

Referring to FIGS. 21-23 and 31, a static trial holder 200 of thepresent invention is shown in side (FIG. 21), top (FIG. 22), perspective(FIG. 23), and side cutaway (FIG. 31) views. In addition, referring toFIGS. 24-26, a sleeve of the static trial holder is shown in sidecutaway (FIG. 24), front (FIG. 25), and back (with partial cutaway)(FIG. 26) views. In addition, referring to FIGS. 27-29, an extension ofthe static trial holder is shown in top (FIG. 27), proximal cutaway(FIG. 28), side (FIG. 29), and distal cutaway (FIG. 30) views.

Referring to FIGS. 32-34 and 44, an alternate static trial holder 2000of the present invention is shown in side (FIG. 32), top (FIG. 33),perspective (FIG. 34), and side cutaway (FIG. 44) views. In addition,referring to FIGS. 35, 36, 37, and 38-39, a sleeve of the alternatestatic trial holder 2000 is shown in side (FIG. 35), top (FIG. 36), sidecutaway (FIG. 37), front (FIG. 38), and back (with partial cutaway)(FIG. 39) views. In addition, referring to FIGS. 40-42, an extension ofthe alternate static trial holder 2000 is shown in top (FIG. 40),proximal cutaway (FIG. 41), side (FIG. 42), and distal cutaway (FIG. 43)views.

The static trial holders 200,2000 are provided primarily for use inholding, inserting and removing the static trials 100,1000 describedherein, or distraction spacers having suitable features therefor, suchas the distraction spacers disclosed in the '127 application.

More specifically, each static trial holder 200,2000 includes a handle202,2020, an extension 204,2040, and a sleeve 206,2060. As shown inFIGS. 31 and 44, the handle 202,2020 and the extension 204,2040 arefixed to one another (preferably by the distal end of the handle202,2020 being fixed to the proximal end of the extension 204,2040) toform a shaft 208,2080. The sleeve 206,2060 surrounds the extension204,2040 and is rotatable with respect to the handle 202,2040 and theextension 204,2040 about the longitudinal axis of the shaft 208,2080.The handle 202,2020 preferably has an flange 232,2320 at its proximalend for use in applying a distally or proximally directed force toposition the static trial 100,1000 (or distraction spacer) into or outof the intervertebral space, and/or for use in helping the surgeonrotate the sleeve 206,2060 with respect to the extension 204,2040 (byengaging the flange 232,2320 and the control knob 219,2190 describedbelow).

The distal end of the extension 204,2040 forms a contractable andexpandable holding enclosure 210,2100 in that the distal end is dividedat a fulcrum 212,2120 into two prongs 214 a-b,2140 a-b, each of whichterminates in a semicircular extent 216 a-b,2160 a-b, each of which hasa tapered end 215 a-b,2150 a-b. The extents 216 a-b,2160 a-b areoriented such that the tapered ends 215 a-b,2150 a-b face one another todefine a radially inwardly tapering mouth 213,2130, and such that thesemicircular openings oppose one another to define the holding enclosure210,2100. The prongs 214 a-b,2140 a-b are spring biased toward a neutralposition (preferably by the formation of the fulcrum 212,2120 incombination with the strength of the material of which the extension204,2040 is made) such that the holding enclosure 210,2100 is springbiased to a receptive state (described below), but the prongs 214a-b,2140 a-b can be brought together to contract the holding enclosure210,2100 to a contracted state, (described below) or the prongs 214a-b,2140 a-b can be further separated to expand the holding enclosure210,2100 to an expanded state (described below).

When the holding enclosure 210,2100 is in the receptive state, the widthof the mouth 213,2130 of the holding enclosure 210,2100 does notaccommodate the diameter of the cylindrical trunk 106,1060 of the statictrial 100,1000 (or distraction spacer) for passage therethrough.However, from this receptive state, the mouth 213,2130 can betemporarily widened (placing the holding enclosure 210,2100 in itsexpanded state) to accommodate the diameter (for passage of thecylindrical trunk 106,1060 through the mouth 213,2130), if a sufficientforce is applied to overcome the neutral position bias of the prongs 214a-b,2140 a-b and thus widen the mouth 213,2130. (Preferably, there isenough space between the outer surfaces of the prongs 214 a-b,2140 a-band the inner surface of the bore 218,2180 of the sleeve, when theprongs 214 a-b,2140 a-b are in their neutral position, so that theprongs 214 a-b,2140 a-b can be separated without interference.) Thesufficient force can be applied by pressing the cylindrical trunk106,1060 against the tapered ends 215 a-b,2150 a-b of the mouth213,2130, in that the separating force component of the radially inwardforce of the pressing will be applied to the semicircular extents 216a-b,2160 a-b by the taper of the tapered ends 215 a-b,2150 a-b. Becausethe holding enclosure 210,2100 is biased toward the receptive state,after the cylindrical trunk 106,1060 is passed through the mouth213,2130 and into the holding enclosure 210,2100, the holding enclosure210,2100 will return to its receptive state in which the width of themouth 213,2130 does not allow passage of the cylindrical trunk 106,1060without the sufficient force. Preferably, the force required to widenthe mouth 213,2130 is greater than gravity and/or the greatest forcethat will be experienced by moving the static trial holder 200,2000prior to placing the holding enclosure 210,2100 in the contracted state.Therefore, once the cylindrical trunk 106,1060 is in the holdingenclosure 210,2100, even before the holding enclosure 210,2100 is placedin its contracted state, the cylindrical trunk 106,1060 will not escapethe holding enclosure 210,2100 as the static trial holder 200,2000 isoriented with the holding enclosure 210,2100 downward, or is movedabout.

It should be understood that when the static trial 100,1000 (ordistraction spacer) is being held (either when the holding enclosure210,2100 is in its receptive state or in its contracted state discussedbelow), because the semicylindrical extents 216 a-b,2160 a-b fit withinthe annular groove 104,1040 of the static trial 100,1000 (or distractionspacer), the static trial 100,1000 (or distraction spacer) will notescape from the enclosure along the longitudinal axis of the cylindricaltrunk 106,1060. That is, as noted above, the recess 102,1020 of eachstatic trial 100,1000 (or distraction spacer) forms an annular groove104,1040 that establishes the cylindrical trunk 106,1060 between thebaseplates of the static trial (or distraction spacer), such that thebaseplates extend as flanges from either end of the cylindrical trunk106,1060. Accordingly, preferably, the opposing semicircular extentseach have a thickness smaller than the width of the annular groove104,1040, and as such fit into the annular groove 104,1040 to engage thecylindrical trunk 106,1060 between them.

In some embodiments, while not shown in FIGS. 1-6 or FIGS. 7-12 or FIGS.21-31 or FIGS. 32-44, it is preferable that the annular groove 104,1040radially widen outwardly, such that the walls of the annular groove104,1040 taper toward one another with the increasing depth of thegroove, such that the floor of the groove is more narrow than theopening 116,1160 of the groove. Accordingly, preferably, in suchembodiments, each semicircular extent 216 a-b,2160 a-b correspondinglyradially widens outwardly, such that the thinner portion of the extent216 a-b,2160 a-b fits closer to the floor of the annular groove104,1040, so that the tapered surfaces 215 a-b,2150 a-b of the extents216 a-b,2160 a-b compress against the tapered walls of the annulargroove 104,1040 when the static trial 100,1000 is engaged by the statictrial holder 200,2000. This taper locking provides for a secure grip sothat the static trial 100,1000 can be manipulated accurately andefficiently.

In some embodiments, while not shown in FIGS. 1-6 or FIGS. 7-12 or FIGS.21-31 or FIGS. 32-44, it is also preferable that the floor of theannular groove 104,1040 of the cylindrical trunk 106,1060 be ridged(e.g., have ridges that run parallel to the longitudinal axis of thecylindrical trunk), and the surfaces of the semicircular extents 216a-b,2160 a-b of the static trial holder 200,2000 that compress againstthe floor of the annular groove 104,1040 when the static trial holder200,2000 engages the static trial 100,1000 be correspondingly providedwith ridges. The interlocking of the ridges of the static trial 100,1000with the ridges of the static trial holder 200,2000 when the statictrial 100,1000 is engaged prevents rotation of the static trial 100,1000about the longitudinal axis of the cylindrical trunk 106,1060 withrespect to the static trial holder 200,2000.

In order to more tightly hold the static trial 100,1000 (or distractionspacer) for manipulation of the static trial 100,1000 (or distractionspacer) during surgical procedures in which greater forces will beexperienced by the static trial 100,1000 (or distraction spacer) and thestatic trial holder 200,2000, the holding enclosure 210,2100 can beplaced in a contracted state. The holding enclosure 210,2100 can beconsidered “unlocked” in its receptive or expanded states, and “locked”in its contracted state, with respect to the nature of the hold that thestatic trial holder 200,2000 potentially can have or has on thecylindrical trunk 106,1060. Preferably, when the holding enclosure210,2100 is locked, a force greater than that which is applicable by anunaided surgeon or nurse (i.e., that which can be applied to remove thecylindrical trunk 106,1060 from the holding enclosure 210,2100 when theholding enclosure 210,2100 is in its receptive state), and greater thanthat which will be experienced by the static trial 100,1000 (ordistraction spacer) and the static trial holder 200,2000 during surgicalprocedures) would be required to pull the cylindrical trunk 106,1060 outof the holding enclosure 210,2100. The placement of the holdingenclosure 210,2100 in its locked state or unlocked state is effected byoperation of a holding assembly that includes the extension 204,2040 andthe sleeve 206,2060 and the manner in which they are configured andinteract.

More particularly, the prongs 214 a-b,2140 a-b can be brought together(or brought closer to one another; it should be understood that theyneed not touch to be encompassed by the present invention), to lock theholding enclosure 210,2100, by a rotation of the sleeve 206,2060 withrespect to the handle 202,2020 and the extension 204,2040 about thelongitudinal axis of the shaft 208,2080. A rotation control knob219,2190 is provided to ease the rotation of the sleeve 206,2060. Asshown in FIGS. 27 and 29-30 in view of FIGS. 24-25 and FIGS. 40 and42-43 in view of FIGS. 35-38, the bore 218,2180 of the sleeve 206,2060(shown in cutaway in FIGS. 25 and 38) defines a cross-section that has awidth 220,2200 that is greater than its depth 222,2220. Further as shownin those figures, the prongs 214 a-b,2140 a-b when separated (shown incutaway in FIGS. 30 and 43) define a cross-section having a width224,2240 that is greater than its depth 226,2260, the width 224,2240 anddepth 226,2260 of the prongs' cross-section being closely accommodatedby the width 220,2200 and depth 222,2220 of the bore's cross-section.When the prongs 214 a-b,2140 a-b are together, the width of prongs'cross-section is closely accommodated by the depth 222,2220 of thebore's cross-section. Thus, when the sleeve 206,2060 is rotated withrespect to the extension 204,2040, the sides of the bore defining thedepth 222,2220 of its cross-section bear against the sides of the prongs214 a-b,2140 a-b defining the width of their cross-section.

It should be noted that in order to ease the rotation of the sleeve206,2060 so that the side of the bore 218,2180 can bear against thesides of the prongs 214 a-b,2140 a-b, the corners of the bore 218,2180are radiused, and at least the sides (that face away from one another)of the prongs 214 a-b,2140 a-b are curved. Preferably, as shown, theprongs 214 a-b,2140 a-b when separated define a partial cylindricalcross-section. The effect of the bearing (of the sides of the bore218,2180 against the sides of the prongs 214 a-b,2140 a-b) is borne bythe space between the prongs 214 a-b,2140 a-b, so that the space narrowsand the prongs 214 a-b,2140 a-b are brought toward one another untilthey are accommodated within the bore's depth 222,2220. The bringingtogether of the prongs 214 a-b,2140 a-b brings the semicircular extents216 a-b,2160 a-b together to place the holding enclosure 210,2100 intoits contracted state, locking it.

Preferably, with regard to the static trial holder 200, the sleeve 206is biased toward establishing the holding enclosure 210 in either anunlocked position or a locked position. Stated alternatively, when theholding enclosure 210 is unlocked (or locked), the force required tobegin rotation of the sleeve 206 is greater than the force required tocontinue rotating the sleeve 206 once rotation has begun. And, as thesleeve 206 is rotated toward a position that will unlock (or lock), theholding enclosure 210, it is biased toward stopping its rotation at thatupcoming position. Stated alternatively, as the sleeve 206 is beingrotated, the force required to rotate the sleeve 206 past that upcomingposition is greater than the force that is required to rotate it priorto reaching that upcoming position.

This biasing of the sleeve 206 of the static trial holder 200 towardpositions that will either unlock or lock the holding enclosure 210 iseffected by the inclusion of at least one spaced recess 228 on the outersurface of the extension 204, and at least one radial bore 230 throughthe wall of the sleeve 206 (preferably through the rotation control knob219 as shown), which bores 230 each have secured therein a springplunger (not shown) (it should be understood that functionallyequivalent devices can also be used in place of a spring plunger).Preferably, each recess 228 is associated with a respective cooperatingbore 230 and spring plunger. When a given bore 230 (and spring plunger)is aligned with its associated recess 228, the sleeve 206 is in aposition at which the holding enclosure 210 is either unlocked orlocked. Each of the spring plungers is biased radially inwardly from theinner surface of the sleeve 206, and as such presses against the outersurface of the extension 204 as the sleeve 206 is being rotated. Thus,when a recess 230 is presented to the spring plunger, it plunges intothe recess 230, stopping the rotation of the sleeve 206. In order torestart (or continue) rotation of the sleeve 206, the bias of the springplunger must be overcome when the restarting (or continuing) rotationalforce is applied. In order to lower the overcoming force required torestart or continue the rotation, the end of the spring plunger ispreferably convexly curvate, and the recess is concavely curvate.Preferably, four recesses 228 and bores 230 (and spring plungers) areprovided, each pair representing one of four quarter-turn rotatedpositions of the sleeve 206. At each position of the sleeve 206, allfour plungers plunge into the recesses 228, securing the sleeve 206 atthat position until a sufficient force is applied to overcome theirplunging bias.

Preferably, with regard to the alternate static trial holder 2000, themovement of the sleeve 2060 toward positions that will either unlock orlock the holding enclosure 2100, and the stopping of the sleeve 2060 atsuch positions, is effected by the inclusion of at least one groove 2280that extends in a 90 degree arc on the outer surface of the extension2040, and at least one radial bore 2300 through the wall of the sleeve2060 (preferably through the rotation control knob 2190 as shown), whichbores 2300 each have secured therein a dog headed screw (not shown) sothat a head of the screw protrudes into interior of the sleeve (itshould be understood that functionally equivalent devices can also beused in place of a dog headed screw). Preferably, each groove 2280 isassociated with a respective cooperating bore 2300 and dog headed screw.When a given bore 2300 (and dog headed screw) is aligned with an end ofits associated groove 2280, the sleeve 2060 is in a position at whichthe holding enclosure 2100 is either unlocked or locked (unlocked whenthe head of the screw is positioned at one end of the groove, lockedwhen it is positioned at the other end of the groove). The head of thedog headed screw protrudes into the interior of the sleeve and into thegroove 2280 and rides therein as the sleeve 2060 is rotated. When an endof the groove 2280 is reached by the head of the screw, the head of thescrew stops against the wall of the groove 2280 at the end of the groove2280, stopping the rotation of the sleeve 2060, and setting the holdingenclosure 2100 to either the unlocked or locked position. In order toset the holding enclosure 2100 to the alternative position, the sleeve2060 is reverse rotated, causing the head of the screw to ride in thegroove 2280 in the opposite direction toward the other end of the groove2280. When the head of the screw reaches the other end of the groove2280, the head of the screw stops against the wall of the groove 2280 atthat end of the groove 2280, stopping the rotation of the sleeve 2060,and setting the holding enclosure 2100 to the alternative position.

Further, with regard to the alternate static trial holder 2000, thesleeve 2060 preferably has on its exterior surface at least one stopprotrusion 1380 that is positioned and dimensioned to extend dorsally orventrally from the exterior surface when the holding enclosure is in its“locked” state (see FIGS. 45-50), so that when the surgeon inserts thestatic trial 100,1000 into the intervertebral space, the stopprotrusions 1380 prevent the static trial 100,1000 from being insertedtoo far into the space (that is, so that the stop protrusions 1380 hitagainst the lips of the adjacent vertebral body endplates before thestatic trial 100,1000 is inserted too far). It should be understood thatstop protrusions can be applied to the static trial holder 200 withoutdeparting from the scope of the invention.

Accordingly, the static trials 100,1000 of the invention (or distractionspacers such as those disclosed in the '127 application) can be held andmanipulated with either static trial holder 200,2000, and from a varietyof approach angles. Holding the handle 202,2020 of the static trialholder 200,2000 in one hand, an operator can push the cylindrical trunk106,1060 of the static trial 100,1000 (or the distraction spacer)against the mouth 213,2130 of the holding enclosure 210,2100 with enoughforce to temporarily expand the mouth 213,2130 to a width that willaccommodate the diameter of the cylindrical trunk 106,1060 for passagethrough the mouth 213,2130. The radially inward tapering of the sides ofthe mouth 213,2130 (the facing ends 215 a-b,2150 a-b of the semicircularextents 216 a-b,2160 a-b of the prongs 214 a-b,2140 a-b) facilitatesthis insertion. It should be noted that, with regard to the alternatestatic trial holder 2000, as shown in FIGS. 45-50 with reference toFIGS. 7 and 43, the depth 2260 of the prongs' cross-section is closelyaccommodated by the depth of the opening establishing by the width ofthe annular groove 1020 of the alternate static trial 1000 and thedepths 1340 of the notches in the pair of opposing notches (1320 a,d,1320 b,d, or 1320 c,f), and the width 2240 of the prongs, cross-sectionis accommodated by the width 1360 of the notches in the pair of opposingnotches (1320 a,d, 1320 b,d, or 1320 c,f), so that the prongs'cross-section fits into the opposing notches as, and when, thecylindrical trunk 1060 is surrounded by the semicircular extents 2160a-b. (That is, that the width 1360 of the notch pair accommodates thewidth 2240 of the static trial holder's 2000 prongs' 2140 a-bcross-section even when the prongs 2140 a-b are separated to place theholding enclosure 2100 in an expanded state as described below. Thisenables the notch pair to accommodate the width 2240 of the prongs'cross-section as the cylindrical trunk 1060 of the static trial 1000 isbeing snapped into the holding enclosure 2100.)

Once the cylindrical trunk 106,1060 has passed into the holdingenclosure 210,2100, the operator can let go of the static trial 100,1000(or distraction spacer) because the prongs 214 a-b,2140 a-b will beovercome by their bias toward their neutral state and thus hold thestatic trial 100,1000 in the holding enclosure 210,2100 to prevent thestatic trial 100,1000 from falling out or slipping out as the statictrial holder 200,2000 is moved with the static trial 100,1000 prior toclosing (e.g., locking) the holding enclosure 210,2100. (When the statictrial 100,1000 (or distraction spacer) is being held in this manner, andthe holding enclosure 210,2100 is unlocked, the static trial 100,1000can be removed from the holding enclosure 210,2100 by a pulling of thestatic trial 100,1000 through the mouth 213,2130 of the holdingenclosure 210,2100 with a force required to again temporarily overcomethe bias of the prongs 214 a-b,2140 a-b toward their neutral state, toseparate them and make the width of the mouth 213,2130 accommodate thediameter of the cylindrical trunk 106,1060.)

With regard to the static trial holder 200, once the operator is readyto lock the holding enclosure 210, while still gripping the handle 202of the static trial holder 200, he rotates the rotation control knob 219either clockwise or counterclockwise to move the sleeve 206 to the nextquarter-turn position. If the rotation control knob 219 is rotated withenough force to cause the spring plungers in the bores 230 to back outof the recesses 228, the sleeve 206 will rotate as desired. Once thesleeve 206 has reached the next quarter-turn position, the springplungers will find the recesses 228 associated with that position, andplunge into the recesses 228 to snap the sleeve 206 into the properposition. As the sleeve 206 rotates, the sides of the sleeve's bore'sinner surface bear against the curved outer surfaces of the prongs 214a-b to push the prongs 214 a-b together so that they are accommodated bythe depth 222 of the bore 218. When the prongs 214 a-b are pressedagainst one another and held in that closed position by the maintenanceof the sleeve 206 in the new position (maintained by the spring plungersin the recesses 228), the semicircular extents 216 a-b move toward oneanother and are correspondingly maintained together about thecylindrical trunk 106,1060. When the prongs 214 a-b are held in thismanner, the cylindrical trunk 106,1060 cannot be removed through themouth 213 of the now-tighter (e.g., locked) holding enclosure 210without the application of forces preferably greater than will beencountered when inserting and removing the static trial 100,1000 fromthe intervertebral space during the surgical procedures. Once the statictrial 100,1000 has been inserted and removed from the intervertebralspace (or the distraction spacer has been inserted and removed from theintervertebral space after being used to distract the space), theoperator can lock the holding enclosure 210 by rotating the sleeve 206another quarter turn (in either the clockwise or the counterclockwisedirection). Again, if the rotation control knob 219 is rotated withenough force to cause the spring plungers to back out of the recesses228, the sleeve 206 will rotate as desired. Once the sleeve 206 hasreached the next quarter-turn position, the spring plungers will findthe recesses 228 associated with that position, and plunge into therecesses 228 to snap the sleeve 206 into the proper position. As thesleeve 206 rotates, the sides of the sleeve's bore's inner surface moveaway from the curved outer surfaces of the prongs 214 a-b and allow theprongs 214 a-b to separate (under their own bias toward the neutralposition) as they are accommodated by the width 220 of the bore 218.When the prongs 214 a-b are separated and allowed to remain in thatposition by the maintenance of the sleeve 206 in the new position(maintained by the spring plungers in the recesses 228), thesemicircular extents 216 a-b are separated from one another and hold thecylindrical trunk 106,1060 against falling or slipping out. That is, thecylindrical trunk 106,1060 can be removed by the operator if theoperator applies a sufficient force to widen the mouth 213 of theholding enclosure 210 enough to let the cylindrical trunk 106,1060 passthrough the mouth 213. Once the static trial 100,1000 (or distractionspacer) is removed, another one can be inserted and manipulated ifrequired.

With regard to the static trial holder 2000, once the operator is readyto lock the holding enclosure 2100, while still gripping the handle 2020of the static trial holder 2000, he rotates the rotation control knob2190 clockwise (or counterclockwise depending on how the grooves 2280are configured; that is, they are illustrated as being configured toenable a locking with a clockwise rotation, and an unlocking with asubsequent counterclockwise rotation, although other embodiments canenable a locking with a counterclockwise rotation, and an unlocking witha clockwise rotation, to accommodate left-handed persons or right-handedpersons or for other reasons) to rotate the sleeve 2060 ninety degreesto the next position. As the sleeve 2060 rotates, the head of the dogheaded screw rides freely in the groove 2280, and the sides of thesleeve's bore's inner surface bear against the curved outer surfaces ofthe prongs 2140 a-b to push the prongs 2140 a-b together so that theyare accommodated by the depth 2220 of the bore 2180. As the dog headedscrew reaches the end of the groove 2280, the prongs 2140 a-b arepressed against one another and the semicircular extents 2160 a-b movetoward one another. The prongs 2140 a-b are held in and biased towardthe closed position, and the semicircular extents 2160 a-b arecorrespondingly maintained together about the cylindrical trunk106,1060, by the fitting of the bore's surfaces against the prongs'surfaces. When the prongs 2140 a-b are held in this manner, thecylindrical trunk 106,1060 cannot be removed through the mouth 2130 ofthe now-tighter (e.g., locked) holding enclosure 2100 without theapplication of forces preferably greater than will be encountered wheninserting and removing the static trial 100,1000 from the intervertebralspace during the surgical procedures.

Further with regard to the static trial holder 2000 engaging the statictrials 1000, the interference between the prongs 2140 a-b and theopposing notches in the notch pair in which the prongs 2140 a-b aredisposed prevents rotation of the static trial 1000 about a longitudinalaxis (e.g., an axis parallel to the longitudinal axis of the cylindricaltrunk 1060) with respect to the static trial holder 2000. That is, ifthe static trial 1000 is encouraged, by forces encountered duringmanipulation of the static trial 1000, to rotate about such an axis withrespect to the static trial holder 2000, the side walls of the notcheswill be confronted by the prong 2140 a-b bodies and such rotationalmovement of the static trial 1000 will be stopped. (As can be seen inFIGS. 46-47, the prongs 2140 a-b are too deep to fit into the annulargroove 1060 without the notch pair accommodating their depth.) The samewill happen if a reverse rotation about such an axis is attempted.

Further with regard to the static trial holder 2000, once the statictrial 100,1000 has been inserted and removed from the intervertebralspace (or the distraction spacer has been inserted and removed from theintervertebral space after being used to distract the space), theoperator can unlock the holding enclosure 2100 by reverse rotating thesleeve 2060 (with enough initial force to overcome the biasing of thefitting of the bore's and the prongs' surfaces) ninety degrees. Again,as the sleeve 2060 rotates, the sides of the sleeve's bore's innersurface move away from the curved outer surfaces of the prongs 2140 a-band allow the prongs 2140 a-b to separate (under their own bias towardthe neutral position) as they are accommodated by the width 2200 of thebore 2180. When the prongs 2140 a-b are separated and allowed to remainin that position by the maintenance of the sleeve 2060 in the newposition (with the head of the dog headed screw against the wall of thegroove 2280 at the other end of the groove 2280), the semicircularextents 2160 a-b are separated from one another and hold the cylindricaltrunk 106,1060 against falling or slipping out. That is, the cylindricaltrunk 106,1060 can be removed by the operator if the operator applies asufficient force to widen the mouth 2130 of the holding enclosure 2100enough to let the cylindrical trunk 106,1060 pass through the mouth2130. Once the static trial 100,1000 (or distraction spacer) is removed,another one can be inserted and manipulated if required. As shown inFIGS. 48-50, in addition to the anterior approach angle shown in FIGS.45-47, the illustrated notch configuration accommodates twoanterior-lateral approach angles as well.

Accordingly, the static trial holder 200,2000 can be used to insert andremove the distraction spacers of the '127 application to distract theintervertebral space as described in the '127, and thereafter (or duringthe distraction) hold to insert and remove the static trials 100,1000 tofind the appropriate size of artificial intervertebral disc to beimplanted.

A preferred embodiment of a dynamic trial of the present invention willnow be described.

Referring now to FIGS. 51-54, a dynamic trial of the present inventionis shown in top (FIG. 51), side (FIG. 52), side cutaway (FIG. 53) andperspective (FIG. 54) views.

The dynamic trial 300 is provided primarily for distracting anintervertebral space according to the procedures described herein and/orfor determining the appropriate size of an artificial intervertebraldisc to be implanted (or whether a particular size can be implanted)into the distracted intervertebral space. While the distraction systemsand methods described in the '127 application, as well as the statictrials described herein (e.g., when used in the manner that thedistraction spacers of the '127 application are used), are also usefulfor distracting an intervertebral space, the dynamic trial 300 isprovided as an additional or alternate distraction tool. Further, whilethe static trials described herein are useful for determining theappropriate size of an artificial intervertebral disc to be implanted(or whether a particular size can be implanted), the dynamic trial 300is provided as an additional or alternate sizing tool.

More specifically, the dynamic trial 300 includes a shaft 302 having abifurcated trial 304 at a distal end of the shaft 302. The trial 304 hasan exterior that is preferably formed like the artificial intervertebraldisc that it is meant to approximate. Accordingly, each half 306 a-b ofthe bifurcated trial 304 has on its outwardly facing surface a convexdome 308 a-b that is shaped like the convex dome of the correspondingbaseplate of the artificial intervertebral disc that the dynamic trial300 approximates (e.g., the convex domes 184 a-b of the baseplates 168a-b of the artificial intervertebral disc 160 of FIGS. 13-20).Preferably, each convex dome 308 a-b is smooth, rather than having aporous coating that is preferred for the convex domes 184 a-b of theartificial intervertebral disc 160, and each half 306 a-b does not havestabilizing spikes such as the stabilizing spikes 188 a-b on theoutwardly facing surfaces 186 a-b of the artificial intervertebral disc160. The omission of these device stabilizing and bone ingrowthencouraging structures and surfaces on the dynamic trial 300 enables thesurgeon to test the size of the artificial intervertebral disc 160 to beimplanted without invading the vertebral body endplates. The shaft 302includes an inner shaft portion 310 that centrally divides at a fulcrum311 into upper and lower distal extensions 312 a-b. The lower distalextension 312 b is fixed to the upper distal extension 312 a at thefulcrum 311, preferably by screws 313 a-b that are plug welded in place.Preferably, as shown, at least the most proximal screw 313 b extendsabove the top surface of the upper distal extension 312 a to serve as abackup stop to prevent extreme forward movement of the control knob 318that is operated to separate the distal extensions 312 a-b (describedbelow).

From the point of division to their distal ends, each of the upper andlower distal extensions 312 a-b are spring biased (preferably by theformation of the fulcrum 311 in combination with the strength of thematerial of which the extensions 312 a-b are made, although the use ofother types of springs is contemplated by the present invention) towardpositions in which they converge toward one another (in the figures, theextensions 312 a-b are shown in these positions). The lower distalextension 312 b is connected (preferably fixed as shown) to the lowerhalf 306 b of the bifurcated trial 304, and the upper distal extension312 a is connected to the upper half 306 a of the bifurcated trial 304.Preferably, as shown, the upper half 306 a is adjustably connected tothe upper distal extension 312 a by a pivot pin 315 that allows theupper half 306 a to rotate about a lateral axis that passes through thelongitudinal and lateral center of the bifurcated trial 304. This axisof rotation allows the upper half 306 a, when separating from the lowerhalf 306 b, to adjust to the orientation of the upper (adjacent)vertebral bone without causing the bone to hinge relative to the lowervertebral bone (the bone adjacent the lower half 306 b).

In order to effect the separation of the upper and lower halves 306 a-b,the shaft 302 further includes an outer shaft potion 314 that islongitudinally translatable adjacent the inner shaft portion 310. Theouter shaft portion 314 preferably straddles the inner shaft portion 310as shown, and includes a pin 316 that passes between the distalextensions 312 a-b. The outer shaft portion 314 is preferablytranslatable distally by the forward movement of a control knob 318 nearthe proximal end of the shaft 302, and translatable proximally bybackward movement of the control knob 318. That is, when the controlknob 318 is pushed distally, the outer shaft portion 314 is movesdistally, and accordingly the pin 316 moves distally. If the pushingforce is great enough to overcome the bias of the divided extensions 312a-b (their bias toward one another), the divided extensions 312 a-b willseparate as the pin 316 moves between them (to make room for the pin316). The separation of the extensions 312 a-b will correspondinglyseparate the halves 306 a-b of the bifurcated trial 304. It should beunderstood that preferably, if the control knob 318 is released, thebias of the divided extensions 312 a-b will press against the pin 316,causing the pin 316 (and correspondingly the outer shaft portion 314 andthe control knob 318) to move proximally to allow the divided extensions312 a-b to return to their biased position, which will bring the halves306 a-b of the trial 304 back together so they can be removed from theintervertebral space. Preferably, markings 320 are provided on the innershaft portion 310 (preferably on its top surface so that the surgeon canmore easily see the markings 320) to quantify the depth (to which thebifurcated trial 304 is expanded) corresponding to the distance that theouter shaft portion 314 is translated with respect to the inner shaftportion 310.

It is anticipated that the pushing force required to separate the halves306 a-b will increase as they separate, due to the compression of thespine seeking to close the intervertebral space and the annulus seekingto prevent the adjacent vertebral discs from separating beyond a certainpoint. Therefore, to provide a mechanical advantage to the operator inthe event that greater distraction is required, but the operator cannotpush the control knob 318 farther with unaided human effort, an finecontrol knob 322 is provided. The fine control knob 322 is preferablythreaded onto the proximal end of the inner shaft portion 310, proximalto the control knob 318. Thus, rotation of the fine control knob 322about the longitudinal axis of the inner shaft portion 310 will causethe body of the fine control knob 322 to press against the control knob318 to move it farther distally. The interference of the threads of thefine control knob-inner shaft portion interface prevents the finecontrol knob 322 from backing up proximally unless the fine control knob322 is reverse rotated to effect that result.

Preferably, as shown, the proximal end 324 of the shaft 302 ispreferably flanged to serve as a slap hammer for impaction (by hittingthe proximal end 324 with a mallet with a distally directed force,e.g.), if necessary for proper positioning of the bifurcated trial 304,and/or forced extraction of the bifurcated trial 304 (by hitting theflange of the proximal end 324 with a mallet with a proximally directedforce, e.g.).

Accordingly, the dynamic trial 300 can be used as an additional oralternative distracting tool (e.g., to the distraction spacers), and/oras an alternative or additional sizing tool (e.g., to the statictrials). As an example of a use for the dynamic trial 300 as analternative or additional distraction tool and an alternative sizingtool, once the intervertebral space is distracted to (or, withoutdistraction, is at) a depth that is at least equal to the depth of theclosed bifurcated trial 304, the bifurcated trial 304 of the dynamictrial 300 can be inserted into the intervertebral space. (If theintervertebral space must be distracted initially because it starts outmore shallow than the depth of the closed bifurcated trial 304, thedistraction spacers of the '127 application and the methods disclosedtherein can be used, e.g.) The control knob 318 and/or fine control knob322 can be operated to separate the halves 306 a-b of the bifurcatedtrial 304 to distract the space as clinically appropriate. Because thebifurcated trial 304 is shaped externally to approximate the artificialintervertebral disc to be implanted (e.g., the artificial intervertebraldisc 160), and because the pivoting of the upper half 306 a of thebifurcated trial 304 allows the halves 306 a-b to appropriatelylordotically orient themselves, when the surgeon determines theintervertebral space to be distracted to its proper dimension (based onhow much compression is being experienced on the dynamic trial 300 andhow tight the annulus is), he can read the markings 320 on the shaft 302to determine what size of artificial intervertebral disc 160 is suitablefor the dimensioned intervertebral space. A subsequent bringing togetherof the halves 306 a-b and a removal of the dynamic trial 300 can then befollowed by insertion of the appropriately sized artificialintervertebral disc 160 (e.g., in manners described below with regard tothe inserter/impactors).

As an example of a use for the dynamic trial 300 as an alternativedistraction tool and an additional sizing tool, after the surgeon hasinitially distracted the intervertebral space (preferably with thedistraction spacers of the '127 application or the static trialsdescribed herein), and applied one or more of the static trials 100,1000to the intervertebral space to determine the appropriate size of theartificial intervertebral disc to be implanted (e.g., the artificialintervertebral disc 160), the surgeon can apply the dynamic trial 300,expand it to the size of the static trial 100,1000 that was determinedto be the appropriate size for the intervertebral space, and thenfurther open the dynamic trial 300 for a final sizing. An example of afinal sizing that would be useful would be to test the amount of fartherdistraction that is clinically possible, without having to remove andreplace static trials 100,1000 when the compression force of the spineand the tension force of the annulus are at their higher levels. Also,the surgeon may wish to distract the space slightly more than the sizeof the appropriately sized static trial 100,1000 or artificialintervertebral disc 160, so that the artificial intervertebral disc 160can be more easily inserted after removal of the static 100,1000 ordynamic trial 300 results in a compressive settling of theintervertebral space. The surgeon may also wish to distract the spaceslightly more than the size of the appropriately sized static trial100,1000 or artificial intervertebral disc 160, to prepare it for easyinsertion of the artificial intervertebral disc 160 to be implanted,with consideration for the height of the stabilizing spikes 188 a-b onthe outwardly facing surfaces 186 a-b of the baseplates 168 a-b of theartificial intervertebral disc 160. While the artificial intervertebraldisc 160 having the spikes 188 a-b can be implanted without theadditional distraction, some surgeons may find such additionaldistraction useful or desirable for a particular case.

Preferred embodiments of inserter/impactors of the present inventionwill now be described.

Referring now to FIGS. 55-58, an inserter/impactor of the presentinvention is shown in side (FIG. 55), top (FIG. 56), side cutaway (FIG.57) and perspective (FIG. 58) views. FIGS. 59-62 show side (FIG. 59),top (FIG. 60), side cutaway (FIG. 61), and perspective (FIG. 62) viewsof an inserter/impactor of the present invention holding a static trialof the present invention. FIGS. 63-64 show top views of aninserter/impactor of the present invention holding a static trial of thepresent invention in two alternative ways. FIGS. 65-68 show side (FIG.65), top (FIG. 66), side cutaway (FIG. 67), and perspective (FIG. 68)views of an inserter/impactor of the present invention holding anexemplary artificial intervertebral disc of the present invention. FIGS.69-70 show top views of an inserter/impactor of the present inventionholding an exemplary artificial intervertebral disc of the presentinvention in two alternative ways.

Referring now to FIGS. 71-82 side (FIG. 71), perspective (FIG. 72), andclose-up perspective (FIG. 73) views of a wedge plate inserter/impactorof the present invention. FIGS. 74-77 show bottom (FIG. 74), side (FIG.75), top (FIG. 76), and side cutaway (FIG. 77) views of a distal end ofa wedge plate inserter/impactor of the present invention. FIGS. 78-79show top (FIG. 78) and side (FIG. 79) views of a wedge plateinserter/impactor of the present invention holding an exemplaryartificial intervertebral disc. FIGS. 80-82 show top (FIG. 80), side(FIG. 81), and side cutaway (FIG. 82) views of a distal end of a wedgeplate inserter/impactor of the present invention holding an exemplaryartificial intervertebral disc.

Each inserter/impactor 400,4000 is provided primarily for holding,inserting, repositioning, removing, impacting, extracting, and otherwisemanipulating an artificial intervertebral disc having features suitablefor being manipulated by the inserter/impactor. (However, they can alsobe used to hold, insert, reposition, remove, impact, extract, andotherwise manipulate the static trials 100,1000 as described above, aswell as any other orthopedic device having suitable features therefor.For example, it should be understood that distraction of anintervertebral space can be accomplished in conjunction with acooperating tool or spacer that can be gripped by theinserter/impactor.) Exemplary suitable artificial intervertebral discsinclude, but are not limited to, the artificial intervertebral disc 160described herein and the artificial intervertebral discs described inthe '032 and '327 patents with regard to FIGS. 8 a-z, 9 a-u, 10 a-u, 11a-k, and 12 a-p thereof and by the accompanying descriptions therefor(e.g., embodiments identified as the first, second, third, fourth, andfifth preferred embodiments of the fourth embodiment family, etc.).Regarding the features suitable for being manipulated by theinserter/impactor 400,4000, such features include those discussed aboveas being suitable features on the static trials 100,1000 and disc 160,namely, an anteriorly facing flat surface on the second (e.g., lower)baseplate of the trial or disc, flanked by two anteriolaterally facingflat surfaces (one on each side of the anteriorly facing flat surface),and, to provide for holding of the trial or disc for an anteriorinsertion approach, a hole spaced from the anteriorly facing flatsurface, the hole having a longitudinal axis parallel to the anteriorlyfacing flat surface. Further regarding the features suitable for beingmanipulated by the wedge plate inserter/impactor 4000, such featuresfurther include the inwardly facing surfaces of the baseplates of thetrial or disc.

More particularly, the inserter/impactor 400,4000 includes a shaft402,4020 having a distal end 404,4040 that has angled flat surfaces 420a-c,4200 a-f corresponding to and fittable against angled flat surfacesof the static trial (e.g., the surfaces 120 a-f,1200 a-f of the statictrial 100,1000) or artificial intervertebral disc (e.g., the surfaces180 a-f of the artificial intervertebral disc 160) to be implanted. Forexample, in an anterior approach for the trial 100,1000 (as shown inFIGS. 59-62 as an example of how either static trial 100,10000 can beengaged by either inserter/impactor 400,4000), 120 a,1200 a and 120d,1200 d facing 420 a (or 4200 a and 4200 d), 120 b,1200 b and 120e,1200 e facing 420 b (or 4200 b and 4200 e), and 120 c,1200 c and 120f,1200 f facing 420 c (or 4200 c and 4200 f), and in an anteriorapproach for the disc 160 (as shown in FIGS. 65-68 as an example of howthe disc 160 can be engaged by either inserter/impactor 400,4000), 180 aand 180 d facing 420 a (or 4200 a and 4200 d), 180 b and 180 e facing420 b (or 4200 b and 4200 e), and 180 c and 180 f facing 420 c (4200 cand 4200 f). Additionally with regard to the wedge plateinserter/impactor 4000, the distal end 4040 has a wedge-shaped extension4042 including upper 4200 g and lower 4200 h wedge surfacescorresponding to and fittable against the inwardly facing surfaces ofthe artificial intervertebral disc (e.g., the lower surface 164 a of theupper baseplate 168 a of the disc 160, and the upper surface 164 b ofthe lower baseplate 168 b of the disc 160, respectively) to beimplanted, causing the baseplates to be angled at a 15 degree lordosisangle, with the lower surface 164 a of the upper baseplate 168 a heldagainst the upper surface 4200 g, and the upper surface of the shieldbeing held against the lower surface 4200 h, as best shown in FIGS.78-82.

In particular with regard to the wedge plate inserter/impactor 4000, theinserter/impactor 4000 holds the disc 160 in a preferred position withrespect to the inserter/impactor 4000. (It should be understood that thesurfaces of the wedge-shaped extension 4042 can be modified within thescope of the present invention to hold the disc 160 (or anotherorthopedic device) at positions other than those illustrated herein.) Inthe illustrated embodiment of the inserter/impactor 4000 in use with thedisc 160, the preferred position is with the baseplates 168 a,b of thedisc 160 angle at 15 degrees of lordosis with respect to one another.More particularly, as best shown in FIGS. 78-82, preferably, the upperand lower surfaces (e.g., 4200 g and 4200 h) of the wedge-shapedextension 4042 protrude from the distal end 4040 and are formed to holdthe baseplates 168 a,b such that they are angled at 15 degrees oflordosis with respect to one another. A surface (e.g., lower surface4200 h) of the wedge-shape extension 4042 that mates with an inwardlyfacing surface of a baseplate (e.g., the lower baseplate 168 b) of adisc (e.g., 160) may be correspondingly shaped (e.g., curved or flat)for interaction or mating with the disc baseplate (e.g., the lowersurface 4200 h of the wedge-shaped extension as illustrated is curved toaccommodate the surface of the shield of the disc). Preferably, theforward surface 4200 i of the wedge-shaped extension 4042 has a concavecurvature towards the shaft 4020 of the inserter/impactor 4000, also foraccommodating the curvature of the surface of the shield of the disc.

Also preferably with regard to the wedge plate inserter/impactor 4000and this preferred positioning, the wedge surfaces of the distal end4040 protrude from a distance midway with respect to the top and bottomof the distal end 4040 and span (e.g., right to left or vice-versa) theentire distal face of the distal end 4040, and the surfaces 4200 d-fabove the wedge on the distal end 4040 are respectively perpendicular tothe wedge's upper surface 4200 g such that each is disposed in parallelwith its respective corresponding surface of the disc 160 when the disc160 is held by the inserter/impactor 4000 at the appropriate lordosisangle. (And, accordingly, are angled approximately 15 degrees withrespect to the surfaces below the wedge 4200 a-c.) Preferably, for ananterior approach, the wedge-shaped extension 4042 is designed andshaped to fit with its antero-lateral confronting surfaces (4200 d,f and4200 a,c) tightly against the correspondingly antero-laterally facingsurfaces (180 d,f and 180 a,c) of the disc 160, but such that itsanterior confronting surfaces (4200 e and 4200 b) are slightly spacedfrom the anteriorly facing surfaces (180 d and 180 b) of the disc 160,when the disc is held by the inserter/impactor 4000. This is primarilyto address manufacturing issues (in some instances, tolerances may notbe adequately defined to ensure that all of those surfaces fit tightlyagainst their corresponding surfaces), so that if there aremanufacturing anomalies, any slight tolerance differences that may existare nevertheless still adequate to ensure at least the tight fitting ofthe antero-lateral confronting surfaces, so that manipulation of thedisc 160 is possible (e.g., in the manner of a wrench against an anglednut). This can be achieved, e.g., by designing the anterior confrontingsurfaces (4200 e and 4200 b) to each be slightly greater in length thanthe corresponding anteriorly facing surfaces (180 e and 180 b) of thedisc baseplates, while still being angled with respect to theantero-lateral confronting surfaces (4200 d,f and 4200 a,c) at the sameangle the antero-laterally facing surfaces (180 d,f and 180 a,c) of thedisc baseplates are angled with respect to the anteriorly facingsurfaces (180 e and 180 b) of the disc. The increased length of theanterior confronting surfaces on the wedge extension results in theslight clearance between the anteriorly facing surfaces (180 e and 180b) of the disc and the corresponding anterior confronting surface (4200e and 4200 b) of the wedged distal end, thereby ensuring that the discwill be fully seated against the antero-lateral confronting surfaces ofthe distal end despite possible manufacturing, material or otherinevitable variations in tolerances of the artificial intervertebraldisc or the inserter/impactor. As noted above, similar in this regard tothe manner in which a wrench engages a nut, this fitting increases themechanical advantage toward repositioning the disc in the intervertebralspace. It should be noted, inasmuch as the inserter/impactor 4000described herein can engage the disc from the antero-lateral angles aswell, the anterior confronting surfaces (4200 e and 4200 b) should alsobe longer than the antero-laterally facing surfaces (180 d,f and 180a,c) of the disc, so that a similar fitting occurs when the disc is heldfrom the antero-lateral angles. Stated broadly, the primary confrontingsurfaces (e.g., the anterior confronting surfaces) of theinserter/impactor are preferably slightly longer than the primaryconfronted surfaces (e.g., anteriorly facing surfaces) of the disc forany given holding orientation.

Each inserter/impactor 400,4000 includes a holding pin 408,4080 thatextends from the center flat surface 420 b,4200 b along a longitudinalaxis of the shaft 402,4020, the pin 408,4080 having a distal end410,4100 that is bent downwardly. The holding pin 408,4080 is springloaded (by a spring 409,4090) in a central channel of the shaft402,4020, so that it is biased toward and against the shaft 402,4020(preferably, the bent end 410,4100 of the pin 408,4080 prevents it fromentering the central channel). With regard to the wedge plateinserter/impactor 4000, the holding pin 4080 is restricted from upwardlylateral movement with respect to the distal end of the inserter/impactor4000 by the presence of the wedge-shaped extension 4042 of the distalend 4040 of the inserter/impactor 4000. More particularly, with anyattempted upward movement of the holding pin 4080, the pin encountersthe upper surface of the channel in which the pin 4080 travels,preventing any such upward movement. On both inserter/impactors400,4000, the holding pin 408,4080 is preferably heat treated (e.g.,cold formed) to increase material quality (e.g., strength).

A flange 411,4110, mechanically connected to the pin 408,4080 andtranslating adjacent the shaft 402,4020, can be pushed distally toovercome the bias of the spring 409,4090 to space the pin 408,4080 awayfrom the central flat surface 420 b,4200 b. (An alternativeconfiguration is one in which the flange 411,4110 and the pin 408,4080are formed from a single piece, rather than being mechanicallyconnected.) In this extended position, the pin 408,4080 can be insertedin the hole 122 b,1220 b,182 b in the baseplate 108 b,1080 b,168 b ofthe static trial 100,1000 or artificial intervertebral disc 160.Releasing the flange 411,4110 allows the spring 409,4090 to pull the pin408,4080 back, causing the anteriorly facing surface 120 b,1200 b,180 bof the baseplate 108 b,1080 b,168 b to be held against the central flatsurface 420 b of the inserter/impactor 400 (or against the lower centralflat surface 4200 b of the inserter/impactor 4000) and theanterioloaterally facing flat surfaces 120 a,c,1200 a,c,180 a,c of thestatic trial 100,1000 or artificial intervertebral disc 160 to be heldagainst the other corresponding flat surfaces 420 a,c of theinserter/impactor 400 (or against the other corresponding flat surfaces4200 a,c of the inserter/impactor 4000). Further and simultaneously,with regard to the wedge plate inserter/impactor 4000, the anteriorlyfacing surface 180 e of the baseplate 168 a is pulled against the uppercentral flat surface 4200 e of the inserter/impactor 4000 and theanterioloaterally facing flat surfaces 180 d,f of the artificialintervertebral disc 160 is pulled against the other corresponding flatsurfaces 4200 d,f of the inserter/impactor 4000. Additionally withregard to the wedge plate inserter/impactor 4000, as noted above, theupper and lower wedge surfaces (4200 g,h) interfere between the inwardlyfacing surfaces 164 a,b of the disc baseplates, causing the baseplatesto be angled at a 15 degree lordosis angle, with the lower surface 164 aof the upper baseplate 168 a held against the upper surface 4200 g, andthe upper surface of the shield being held against the lower surface4200 h, as best shown in FIGS. 78-82.

A knob 412,4120, threaded on the shaft 402,4020, can be rotated aboutthe longitudinal axis of the shaft 402,4020 to push the flange 411,4110farther proximally, to pull the pin 409,4090 tighter and therefore lockits position (the interference of the threads of the knob-shaftinterface prevents the knob 412,4120 from moving distally unless theknob 412,4120 is reverse rotated to effect that result) to more securelyhold the baseplate 108 b,1080 b,168 b, and reverse rotated to unlock andloosen the pin 409,4090.

When the static trial 100,1000 or disc 160 is held in this manner,rotation of the static trial 100,1000 or disc 160 about a longitudinalaxis (of the static trial 100,1000 or disc 160) relative to theinserter/impactor 400,4000 is prevented by interference of the cornersof the static trial's 100,1000 or disc's 160 flat surfaces 120 a-c,1200a-c,180 a-c and the corners of the inserter/impactor's 400,4000 flatsurfaces 420 a-c,4200 a-f, similar to the manner in which a wrenchholding a nut prevents rotation of the nut relative to the wrench.Further, the holding of the static trial 100,1000 or disc 160 in thismanner allows for some repositioning of the static trial 100,1000 ordisc 160 in the intervertebral space via rotation of the static trial100,1000 or disc 160 in either direction about the longitudinal axis ofthe intervertebral space.

Further, with regard to the wedge plate inserter/impactor 4000, when thestatic trial 100,1000 or disc 160 is held in this manner, rotation ofthe static trial 100,1000 or disc 160 about a lateral axis (of thestatic trial 100,1000 or disc 160) relative to the inserter/impactor4000 is prevented by interference of the inwardly facing surface (e.g.,164 a) of the first baseplate (e.g., upper baseplate) of the statictrial 100,1000 or disc 160 and the upper surface 4200 g of the wedge onthe distal end 4040, and by interference of the inwardly facing surface(e.g., 164 b) of the second baseplate (e.g., lower baseplate) of thestatic trial 100,1000 or disc 160 and the lower surface 4200 h of thewedge on the distal end 4040. Accordingly, the holding of the statictrial 100,1000 or disc 160 in this manner allows for some repositioningof the static trial 100,1000 or disc 160 in the intervertebral space viarotation of the static trial 100,1000 or disc 160 in either directionabout the longitudinal or latitudinal axis of the intervertebral space.

In some embodiments of the wedge plate inserter/impactor 4000, when theartificial intervertebral disc 160 is held by the inserter/impactor4000, the flat surfaces 180 a-c are more closely confronted by theangled flat surfaces 4200 a-c of the inserter/impactor 4000, comparedwith the flat surfaces 180 d-f being less closely confronted by theangled flat surfaces 4200 d-f of the inserter/impactor 4000. As such,the structure of the artificial intervertebral disc 160 having the flatsurfaces 180 d-f (e.g., the upper baseplate 168 a) has slightly morerotation and angulation freedom relative to the inserter/impactor 4000when being held, compared to the structure of the artificialintervertebral disc 160 having the flat surfaces 180 a-c (e.g., thelower baseplate 168 b). This permits the artificial intervertebral disc160 to adjust to the intervertebral space (e.g., to the angulation ofthe adjacent vertebral endplates, defining the intervertebral space,relative to one another) as it is being inserted thereinto. That is,typically, the adjacent vertebral endplates will be lordotically angledwith respect to one another as a result of the intervertebral spacebeing prepared and distracted.

Preferably, both of the baseplates of the static trial 100,1000 or disc160 have similarly configured flat surfaces. For example, the lowerbaseplate's 108 b,1080 b,168 b flat surfaces 120 a-c,1200 a-c,180 a-chave similarly configured and similarly oriented counterpart flatsurfaces 120 d-f,1200 d-f,180 d-f on the upper baseplate 108 a,1080a,168 a. Further preferably, both baseplates' 108 a-b,1080 a-b,168 a-bflat surfaces 120 a-f,1200 a-f,180 a-f face the angled flat surfaces 420a-c,4200 a-f of the inserter/impactor 400,4000 when the static trial100,1000 or disc 160 is held by the inserter/impactor 400,4000. Forexample, in an anterior approach for the trial 100,1000 (as shown inFIGS. 59-62 as an example of how either trial 100,1000 can be held byeither inserter/impactor 400,4000), 120 a,1200 a and 120 d,1200 d facing420 a (or 4200 a and 4200 d), 120 b,1200 b and 120 e,1200 e facing 420 b(or 4200 b and 4200 e), and 120 c,1200 c and 120 f,1200 f facing 420 c(or 4200 c and 4200 f), and in an anterior approach for the disc 160 (asshown in FIGS. 65-68), 180 a and 180 d facing 420 a (or 4200 a and 4200d), 180 b and 180 e facing 420 b (or 4200 b and 4200 e), and 180 c and180 f facing 420 c (or 4200 c and 4200 f).

It should be noted that preferably, when the static trial 100,1000 isheld by the inserter/impactor 400,4000, the flat surfaces 120 a-c,1200a-c and the counterpart flat surfaces 120 d-f,1200 d-f are tightly heldagainst the angled flat surfaces 420 a-c,4200 a-f of theinserter/impactor 400,4000 as described above. It is also preferablethat the baseplates 108 a-b,1080 a-b of each of the plurality of statictrials 100,1000 be appropriately lordotically angled relative to oneanother to ease insertion of the static trial 100,1000 into theintervertebral space and to mimic how the artificial intervertebral disc160 will typically be oriented as it is being inserted using theinserter/impactor 400,4000. While not shown in FIGS. 1-6 or FIGS. 7-12,in some embodiments, when the static trials 100,1000 are formed in sucha lordotically oriented configuration, it is preferable that the flatsurfaces 120 d-f,1200 d-f on the first (e.g., upper) baseplate 108a,1080 a be parallel to the flat surfaces 120 a-c,1200 a-c of the second(e.g., lower) baseplate 108 b,1080 b in the static trial's 100,1000appropriately lordotically oriented configuration, so that when thestatic trial 100,1000 is held tightly by the inserter/impactor 400,4000,the flat surfaces 120 a-f,1200 a-f are flush with the flat surfaces 420a-c,4200 a-f of the inserter/impactor 400,4000 even though thebaseplates 108 a-b,1080 a-b are lordotically oriented configuration, itis preferable that the flat surfaces 120 d-f,1200 d-f on the first(e.g., upper) baseplate 108 a,1080 a be parallel to the flat surfaces120 a-c,1200 a-c of the second (e.g., lower) baseplate 108 b,1080 b inthe static trial's 100,1000 appropriately lordotically orientedconfiguration, so that when the static trial 100,1000 is held tightly bythe inserter/impactor 400,4000, the flat surfaces 120 a-f,1200 a-f areflush with the flat surfaces 420 a-c,4200 a-f of the inserter/impactor400,4000 even though the baseplates 108 a-b,1080 a-b are lordoticallyangled with respect to one another.

With regard to the inserter/impactor 400, by contrast, preferably, whenthe artificial intervertebral disc 160 is held by the inserter/impactor400, the flat surfaces 180 a-c are tightly held against the angled flatsurfaces 420 a-c of the inserter/impactor 400 as described above, butthe counterpart flat surfaces 180 d-f are loosely held against theangled flat surfaces 420 a-c of the inserter/impactor 400. As such, thestructure of the artificial intervertebral disc 160 having thecounterpart flat surfaces 180 d-f (e.g., the upper baseplate 168 a) isable to angulate and rotate to a limited extent relative to thestructure of the artificial intervertebral disc 160 having the flatsurfaces 180 a-c. This permits the artificial intervertebral disc 160 toadjust to the intervertebral space (e.g., to the angulation of theadjacent vertebral endplates, defining the intervertebral space,relative to one another) as it is being inserted thereinto. That is,typically, the adjacent vertebral endplates will be lordotically angledwith respect to one another as a result of the intervertebral spacebeing prepared and distracted. As the artificial intervertebral disc 160is then inserted into the intervertebral space using theinserter/impactor 400, then, the baseplates 168 a-b will be permitted tolordotically angle with respect to one another to squeeze into theintervertebral space.

With regard to the wedge plate inserter/impactor 4000, when theartificial intervertebral disc 160 is held by the inserter/impactor4000, the wedge surfaces of the distal end 4040 protrude from a distancemidway with respect to the top and bottom of the distal end 4040 andspan (e.g., right to left or vice-versa) the entire distal face of thedistal end 4040, and the surfaces 4200 d-f above the wedge on the distalend 4040 are respectively perpendicular to the wedge's upper surface4200 g such that each is disposed in parallel with its respectivecorresponding surface of the disc 160 when the disc 160 is held by theinserter/impactor 4000 at the appropriate lordosis angle. (And,accordingly, are angled approximately 15 degrees with respect to thesurfaces below the wedge 4200 a-c.) Preferably, for an anteriorapproach, the wedge-shaped extension 4042 is designed and shaped to fitwith its antero-lateral confronting surfaces (4200 d,f and 4200 a,c)tightly against the correspondingly antero-laterally facing surfaces(180 d,f and 180 a,c) of the disc 160, but such that its anteriorconfronting surfaces (4200 e and 4200 b) are slightly spaced from theanteriorly facing surfaces (180 d and 180 b) of the disc 160, when thedisc is held by the inserter/impactor 4000. This is primarily to addressmanufacturing issues (in some instances, tolerances may not beadequately defined to ensure that all of those surfaces fit tightlyagainst their corresponding surfaces), so that if there aremanufacturing anomalies, any slight tolerance differences that may existare nevertheless still adequate to ensure at least the tight fitting ofthe antero-lateral confronting surfaces, so that manipulation of thedisc 160 is possible (e.g., in the manner of a wrench against an anglednut). This can be achieved, e.g., by designing the anterior confrontingsurfaces (4200 e and 4200 b) to each be slightly greater in length thanthe corresponding anteriorly facing surfaces (180 e and 180 b) of thedisc baseplates, while still being angled with respect to theantero-lateral confronting surfaces (4200 d,f and 4200 a,c) at the sameangle the antero-laterally facing surfaces (180 d,f and 180 a,c) of thedisc baseplates are angled with respect to the anteriorly facingsurfaces (180 e and 180 b) of the disc. The increased length of theanterior confronting surfaces on the wedge extension results in theslight clearance between the anteriorly facing surfaces (180 e and 180b) of the disc and the corresponding anterior confronting surface (4200e and 4200 b) of the wedged distal end, thereby ensuring that the discwill be fully seated against the antero-lateral confronting surfaces ofthe distal end despite possible manufacturing, material or otherinevitable variations in tolerances of the artificial intervertebraldisc or the inserter/impactor. As noted above, similar in this regard tothe manner in which a wrench engages a nut, this fitting increases themechanical advantage toward repositioning the disc in the intervertebralspace. It should be noted, inasmuch as the inserter/impactor 4000described herein can engage the disc from the antero-lateral angles aswell, the anterior confronting surfaces (4200 e and 4200 b) should alsobe longer than the antero-laterally facing surfaces (180 d,f and 180a,c) of the disc, so that a similar fitting occurs when the disc is heldfrom the antero-lateral angles. Stated broadly, the primary confrontingsurfaces (e.g., the anterior confronting surfaces) of theinserter/impactor are preferably slightly longer than the primaryconfronted surfaces (e.g., anteriorly facing surfaces) of the disc forany given holding orientation.

Also preferably, in order to provide for a holding of the static trial100,1000 or disc 160 for two additional (here, anteriolateral) insertionapproaches, each static trial 100,1000 or disc 160 also includes twoadditional holes 122 a,1220 a,182 a and 122 c,1220 c,182 c, one (e.g.,122 a,1220 a,182 a) spaced apart from one of the anteriolaterally facingflat surfaces (e.g., 120 a,1200 a,180 a), and the other (e.g., 122c,1220 c,182 c) spaced apart from the other of the anteriolaterallyfacing flat surfaces (e.g., 120 c,1200 c,180 c). Accordingly, operationof the inserter/impactor 400,4000 can fit the holding pin 408,4080 intoeither of these two additional holes 122 a,1220 a,182 a or 122 c,1220c,182 c, and hold the associated anteriolaterally facing flat surface(the one associated with the hole into which the pin 408,4080 is fit) ofthe static trial 100,1000 or disc 160 against the flat surface of theinserter/impactor 400,4000 opposite the pin 408,4080. For example, in afirst anteriolateral approach for the trial 100,1000 (as shown in FIG.63 as an example of how either trial 100,1000 can be engaged by eitherinserter/impactor 400,4000), 120 a,1200 a and 120 d,1200 d notconfronted, 120 b,1200 b and 120 e,1200 e facing 420 a (or 4200 a and4200 d), and 120 c,1200 c and 120 f,1200 f facing 420 b (or 4200 b and4200 e), and a first anteriolateral approach for the disc 160 (as shownin FIG. 69 as an example of the how the disc 160 can be engaged byeither inserter/impactor 400,4000), 180 a and 180 d not confronted, 180b and 180 e facing 420 a (or 4200 a and 4200 d), and 180 c and 180 ffacing 420 b (or 4200 b and 4200 e). And, for example, in a secondanteriolateral approach for the trial 100 (as shown in FIG. 64 as anexample of how either trial 100,1000 can be engaged by eitherinserter/impactor 400,4000), 120 a,1200 a and 120 d,1200 d facing 420 b(or 4200 b and 4200 e), 120 b,1200 b and 120 e,1200 e facing 420 c (or4200 c and 4200 f), and 120 c,1200 c and 120 f,1200 f not confronted,and a second anteriolateral approach for the disc 160 (as shown in FIG.70 as an example of how the disc 160 can be engaged by eitherinserter/impactor 400,4000), 180 a and 180 d facing 420 b (or 4200 b and4200 e), 180 b and 180 e facing 420 c (or 4200 c and 4200 f), and 180 cand 180 f not confronted.

It should be understood that preferably, in order to facilitate theseadditional approaches, the angle separating the anteriorly facing flatsurface of the static trial 100,1000 or disc 160 and one of theanteriolaterally facing flat surfaces of the static trial 100,1000 ordisc 160 is equal to the angle separating the anteriorly facing flatsurface and the other of the anteriolaterally facing flat surfaces.Preferably, the surfaces are angled with respect to one another at anangle of 33.4 degrees.

It should also be understood that the inclusion of additional adjacentangulated surfaces (or placing the angulated surfaces in other locationson the trial or disc or other orthopedic device), and/or includingcorresponding holes adjacent to such surfaces, can provide the surgeonwith additional approaches, e.g., other anteriolateral approaches,directly lateral approaches, posteriolateral approaches, and/or directlyposterior approaches. For example, a trial or disc can have angledsurfaces (and corresponding holes) along the entire perimeter of one orboth of the baseplates, and thus enable the surgeon to engage the trialor disc from a number of angles, including anterior, posterior, lateral,anteriolateral, and posteriolateral angles.

The inserter/impactor 400,4000 further includes at a proximal end a cap414,4140 for use as an impact surface if the trial 100,1000 or disc 160must be impacted further into the intervertebral space after insertion,or forcibly extracted from the intervertebral space. A mallet can beused to strike the cap 414,4140 (in a distal direction for impaction, orin a proximal direction (using the flange of the cap 414,4140) forextraction). It should be noted a striking of the cap 414,4140 willtranslate the striking force to the baseplates through the shaft402,4020 and the flat surfaces, but will not damage the holding pin408,4080 because the holding pin 408,4080 is spring loaded in thecentral channel and thus buffered from the striking force thereby. Thedistal end 404,4040 of the inserter/impactor 400,4000 further preferablyincludes at least one vertebral body stop (e.g., 4202) that protrudeslongitudinally with respect to the shaft 402,4020, from the surfaces ofthe distal end. The stops help prevent the inserter/impactor from beingused to insert the disc (or other orthopedic device) too far into theintervertebral space.

Accordingly, the inserter/impactor 400,4000 can be used to grip eitherthe static trials or the artificial intervertebral disc to be implanted,and hold the same during insertion and/or removal of the same, and isuseful for a variety of surgical approach angles.

Preferred embodiments of a repositioner/extractor of the presentinvention will now be described.

Referring now to FIGS. 83-85, a symmetric repositioner/extractor of thepresent invention is shown in side (FIG. 83), top (FIG. 84), andperspective (FIG. 85) views. And referring now to FIGS. 86-88, an offsetleft repositioner/extractor of the present invention is shown in side(FIG. 86), top (FIG. 87), and perspective (FIG. 88) views. And referringnow to FIGS. 89-91, an offset right repositioner/extractor of thepresent invention is shown in side (FIG. 89), top (FIG. 90), andperspective (FIG. 91) views. And referring now to FIG. 92-94, analternative offset left repositioner/extractor of the present inventionis shown in side (FIG. 92), top (FIG. 93), and perspective (FIG. 94)views. And referring now to FIGS. 95-97, an alternative offset rightrepositioner/extractor of the present invention is shown in side (FIG.95), top (FIG. 96), and perspective (FIG. 97) views.

Each repositioner/extractor is provided primarily for repositioningand/or extracting a static trial or artificial intervertebral dischaving features suitable for being manipulated by therepositioner/extractor. Exemplary suitable artificial intervertebraldiscs are described in the '032 and '327 patents with regard to FIGS. 8a-z, 9 a-u, 10 a-u, 11 a-k, and 12 a-p thereof and by the accompanyingdescriptions therefor (e.g., embodiments identified as the first,second, third, fourth, and fifth preferred embodiments of the fourthembodiment family, etc.). Regarding the features suitable for beingmanipulated by each repositioner/extractor, such features include atleast two holes extending longitudinally into one of the baseplates ofthe static trial or artificial intervertebral disc from the inwardlyfacing surface of the baseplate. More than two holes can be used toprovide for multiple repositioning/extracting approaches. Preferably, inorder for the same repositioning/extracting tool to be used for multipleapproaches on the same trial or artificial intervertebral disc, adjacentholes should be separated by the same distance separating other adjacentholes.

In order to engage the two holes, each repositioner/extractor has twopins extending in parallel from a central shaft, perpendicular to thelongitudinal axis of the central shaft. The pins are spaced to engagethe two holes simultaneously, and each pin has a diameter smaller thanthe diameter of the hole it is to engage. Therefore, the pins can beinserted into the holes, and pulling or pushing on the central shaftalong its longitudinal axis when the holes are engaged pulls or pushesthe static trial or artificial intervertebral disc in the intervertebralspace. Further, because two holes are engaged, the static trial orartificial intervertebral disc can be rotated in either direction abouta longitudinal axis passing through the intervertebral space, byrotating of the central shaft of the repositioner/extractor about itsdistal end, about an axis parallel to the longitudinal axes of the pins.A handle at a proximal end of the central shaft is useful for pushing orpulling on the shaft. A flange adjacent the proximal end of the shaft isuseful for impaction (either with a distally directed force or aproximally directed force), if necessary to manipulate the shaft.

On each repositioner/extractor, the pins are formed on prongs thatextend laterally from the central shaft. The direction of the prongs,and the location of the pins relative to the central shaft, determinethe angle or angles of surgical approach for which a particularrepositioner/extractor can be used. Further, the number and location ofholes further determine the angle or angles of surgical approach forwhich a particular repositioner/extractor can be used. Accordingly, thepresent invention contemplates a variety of repositioner/extractors, anda variety of holes configurations, to provide the surgeon with a varietyof possible surgical approach angles.

For example, three repositioner/extractors are illustrated, and, forexample, two hole configurations are illustrated.

The first, symmetric, repositioner/extractor 500, shown in FIGS. 83-85,includes a shaft 502 having a distal end that is symmetrically dividedinto two prongs 504 a-b, each of the prongs having a pin 506 a-bextending upwardly and parallel to the pin on the other prong. Thesecond and third, left offset and right offset, repositioners/extractors510,520, shown in FIGS. 86-88 and 89-91, respectively, each include ashaft 512,522 having a distal end that bends diagonally laterally, theleft offset distal end 514 bending in one direction (e.g., to the left),the right offset distal end 524 bending in an opposite direction (e.g.,to the right). The distal end of each of the second and thirdrepositioners/extractors 510,520 has two pins 516 a-b,526 a-b seriallyspaced on the bent portion, and each of the pins extends upwardly andparallel to the other pin. (As shown in FIGS. 92-94 and 95-97,alternative embodiments 530,540 of the second and third, left offset andright offset, repositioners/extractors each include a shaft 532,542having a distal end that has a straight prong 534 a,544 a and a curvedlateral prong 534 b,544 b, where the curved lateral prong 534 b extendsin one direction (e.g., left) for the alternative left offsetrepositioner/extractor 530, and where the curved lateral prong 544 bextends in an opposite direction (e.g., right) for the alternative rightoffset repositioner/extractor 540. Each of the prongs 534 a-b,544 a-bhas a pin 536 a-b,546 a-b extending upwardly and parallel to the pin onthe other prong. The alternative repositioners/extractors 530,540, eachhaving a space between the pins 536 a,b,546 a,b, provides for avoidanceof any structures on the static trial or artificial intervertebral discthat may be present between the holes.) On each of therepositioners/extractors 500,510,520,530,540, the pins are spaced sothat they simultaneously each fit into a respective one of the twoadjacent holes in the baseplate of the static trial or artificialintervertebral disc. Each of the repositioners/extractors500,510,520,530,540 has a handle 508,518,528,538,548 at a proximal endof the central shaft which is useful for pushing or pulling on theshaft, and a flange 509,519,529,539,549 adjacent the proximal end of theshaft that is useful for impaction (either with a distally directedforce or a proximally directed force), if necessary to manipulate theshaft.

As noted above, the repositioner/extractor that is appropriate ordesired for a given case depends at least in part on the configurationof the holes in the baseplates. Two hole configurations are disclosed,as examples of suitable configurations, although other configurationsare possible and contemplated by the present invention. A first holeconfiguration includes three holes on one of the baseplates, the holesbeing configured so that a first hole is located in theanterior-posterior plane, and the adjacent (second and third) holes arelocated in respective opposing anteriolateral planes on either side ofthe first hole. This hole configuration is shown in FIGS. 98-103, eachof which shows a top cutaway view of the artificial intervertebral discof FIGS. 13-20, showing its lower baseplate, having the first holeconfiguration, engaged by one of the repositioners/extractors500,510,520. Each view of the lower baseplate shows the first hole 550,the second hole 552, and the third hole 554 of the first holeconfiguration.

A second hole configuration includes four holes on one of thebaseplates, the holes being configured so that first and second holesstraddle the anterior-posterior plane, a third hole is located so thatthe third hole and the first hole straddle one of the opposinganteriolateral planes, and a fourth hole is located so that the fourthhole and the second hole straddle the other of the opposinganteriolateral planes. This hole configuration is shown in FIGS.104-112, each of which shows a bottom cutaway view of the artificialintervertebral disc of FIGS. 13-20, showing its upper baseplate, havingthe second hole configuration, engaged by one of therepositioners/extractors 500,510,520. Each view of the upper baseplateshows the first hole 560, the second hole 562, the third hole 564, andthe fourth hole 566, of the second hole configuration.

It should be understood that configurations having more or fewer holes,and in a variety of locations, are contemplated by the invention, andthe detailed descriptions of only two hole configurations is not meantto limit the invention to only these two configurations. Importantly,the invention encompasses using a hole or any number of holes, bored atany suitable angle, whether parallel to other holes or not, in anynumber of locations on a spacer, a trial or an artificial intervertebraldisc (not limited to locations on the baseplates), for purposes ofenabling the spacer, trial, or disc to be engaged by a manipulationinstrument (not limited to a repositioner/extractor) that engages thehole, and/or to enable the surgeon to work from a variety of approaches.For example, as described in more detail below, the first and secondhole configurations described herein, in cooperation with therepositioner/extractors, provide the surgeon with the ability to workfrom a directly anterior approach, as well as several anteriolateralapproaches. It should be understood that additional hole configurationscan enable the surgeon to work from a directly posterior approach,posteriolateral approaches, directly lateral approaches, oranteriolateral approaches that are different that those illustrated. Forexample, the placement of one or more suitably spaced holes (or theaddition of one or more holes) on the posterior edge, and/or one or bothof the lateral edges of one or both of the baseplates, would enable thesurgeon to use the repositioner/extractors of the present invention toachieve such approaches.

As noted above, and referring now to FIGS. 98-112, it can be seen thateach of the repositioner/extractors can be used in more than one mannerdepending on the tool desired and the approach desired. For example,with reference to FIGS. 98-99, regarding the first hole configuration(three holes in one of the baseplates), the symmetricrepositioner/extractor 500 can be used in either of two anteriolateralapproaches (see FIGS. 98-99). That is, the symmetricrepositioner/extractor's shaft 502 can be inserted into the wound fromeither of the two anteriolateral approaches, and the pins 506 a-b can beinserted into the first 550 and second 552 holes (for one of the twoanteriolateral approaches) (FIG. 98) or the first 550 and third 552holes (for the other of the two anteriolateral approaches) (FIG. 99) ofthe first hole configuration.

Also, for example, with reference to FIGS. 100-103, regarding the firsthole configuration, each of the left offset repositioner/extractor 510and the right offset repositioner/extractor 520 can be used in either adirectly anterior approach (FIGS. 100,102) or a respectiveanteriolateral approach (FIGS. 101,103). That is, the right offsetrepositioner/extractor's shaft 522 can be inserted into the wound from adirect anterior approach, and the right offset repositioner/extractor'spins 526 a-b can then be placed into the first 550 and second 552 holesof the first hole configuration (FIG. 100). And, the right offsetrepositioner/extractor's shaft 522 can be inserted into the wound froman anteriolateral approach, and the right offsetrepositioner/extractor's pins 526 a-b can then be placed into the first550 and third 554 holes of the first hole configuration (FIG. 101). And,the left offset repositioner/extractor's shaft 512 can be inserted intothe wound from a direct anterior approach, and the left offsetrepositioner/extractor's pins 516 a-b can then be placed into the first550 and third 554 holes of the first hole configuration (FIG. 102). And,the left offset repositioner/extractor's shaft 512 can be inserted intothe wound from an anteriolateral approach, and the left offsetrepositioner/extractor's pins 516 a-b can then be placed into the first550 and second 552 holes of the first hole configuration (FIG. 103). Itshould be noted that the alternate left offset 530 and alternate rightoffset 540 repositioners/extractors can also fit into the holes of thefirst hole configuration in the same manner as described here withregard to the left offset 510 and right offset 520repositioners/extractors.

Also, for example, with reference to FIGS. 104-112, regarding the secondhole configuration (four holes in one of the baseplates), the symmetricrepositioner/extractor 500 can be used in a directly anterior approach(FIG. 104), and either of two anteriolateral approaches (FIGS. 105-106).That is, the symmetric repositioner/extractor's shaft 502 can beinserted into the wound from a directly anterior approach, and the pins506 a-b can be inserted into the first 560 and second 562 holes of thesecond hole configuration (FIG. 104). And, the symmetricrepositioner/extractor's shaft 502 can be inserted into the wound fromeither of the two anteriolateral approaches, and the pins 506 a-b can beinserted into the first 560 and third 564 holes (for one of the twoanteriolateral approaches) (FIG. 105) or the second 562 and fourth 566holes (for the other of the two anteriolateral approaches) (FIG. 106) ofthe second hole configuration.

Also, for example, with reference to FIGS. 107-112, regarding the secondhole configuration, each of the left offset repositioner/extractor 510and the right offset repositioner/extractor 520 can be used in any ofthree respective anteriolateral approaches. That is, the right offsetrepositioner/extractor's shaft 522 can be inserted into the wound fromany of its three possible anteriolateral approaches, and the rightoffset repositioner/extractor's pins 526 a-b can then be placed into thefirst 560 and second 562 holes (FIG. 107) (for a first of the threeanteriolateral approaches), the first 560 and third 564 holes (FIG. 108)(for a second of the three anteriolateral approaches), or the second 562and fourth 566 holes (FIG. 109) (for a third of the three anteriolateralapproaches). And, the left offset repositioner/extractor's shaft 512 canbe inserted into the wound from any of its three possible anteriolateralapproaches, and the left offset repositioner/extractor's pins 516 a-bcan then be placed into the first 560 and second 562 holes (FIG. 110)(for a first of the three anteriolateral approaches), the first 560 andthird 564 holes (FIG. 111) (for a second of the three anteriolateralapproaches), or the second 562 and fourth 566 holes (FIG. 112) (for athird of the three anteriolateral approaches). It should be noted thatthe alternate left offset 530 and alternate right offset 540repositioners/extractors can also fit into the holes of the second holeconfiguration in the same manner as described here with regard to theleft offset 510 and right offset 520 repositioners/extractors.

It should be noted from the illustrations in FIGS. 98-112 that theanteriolateral approaches are at a variety of angles relative to theanterior-posterior plane, and further that the illustrated angles aremerely exemplary. That is, the invention encompasses additional approachangles, in that such additional approach angles are possible by (asdescribed above) adding or deleting holes, and/or changing the locationof holes, and/or changing the spacing between holes (in conjunction withchanging the spacing between pins), and/or changing the angle at whichthe offset repositioner/extractors' pins are placed relative to oneanother and to the shaft of such repositioner/extractors.

As discussed above, once the pins are established in the two adjacentholes, manipulating the shaft of the repositioner/extractor willreposition the static trial or artificial intervertebral disc in theintervertebral space and/or extract it from the intervertebral space.The use of more than one pin (versus one pin) enables the static trialor artificial intervertebral disc to be rotated in either directionabout a longitudinal axis passing through the intervertebral space.

A preferred embodiment of a leveler of the present invention will now bedescribed.

Referring now to FIGS. 113-117, a leveler of the present invention isshown in bottom (FIG. 113), side (FIG. 114), front (FIG. 115), toppartial perspective (FIG. 116), and bottom partial perspective (FIG.117) views. More particularly, FIG. 116 shows a top perspective view ofthe distal end of the leveler, and FIG. 117 shows a bottom perspectiveview of the distal end of the leveler.

The leveler is provided primarily for establishing a parallelorientation of the baseplates (relative to one another), and/or securingthe purchase of the stabilizing spikes, of an artificial intervertebraldisc having features suitable for being manipulated by the leveler.Exemplary suitable artificial intervertebral discs are described in the'032 and '327 patents with regard to FIGS. 8 a-z, 9 a-u, 10 a-u, 11 a-k,and 12 a-p thereof and by the accompanying descriptions therefor (e.g.,embodiments identified as the first, second, third, fourth, and fifthpreferred embodiments of the fourth embodiment family, etc.). Regardingthe features suitable for being manipulated by the leveler, suchfeatures include suitably formed inwardly facing surfaces of thebaseplates of the artificial intervertebral disc.

More particularly, the leveler 600 includes a shaft 602 having a forkeddistal end formed by two opposing tongs 604 a-b that are symmetric toone another about a longitudinal axis of the shaft 602. Each of thetongs 604 a-b has an extent that initially curves laterally outward awayfrom the shaft 602 and from the other tong's extent, to define a centralpocket 606 forward of the shaft 602 between the tongs' extents. Eachtong's extent then resumes a distal direction to become parallel to theshaft 602 and to the other tong's extent.

Each tong's extent has an upper surface 608 a-b and a lower surface 610a-b. The upper surface 608 a-b is preferably shaped to conform againstthe inwardly facing surface of a first (e.g., upper) baseplate of anartificial intervertebral disc, and the lower surface 610 a-b ispreferably shaped to conform against the inwardly facing surface of asecond (e.g., lower) baseplate of the artificial intervertebral disc, sothat insertion of the forked distal end of the leveler 600 between thebaseplates, with the central pocket 606 of the distal end avoiding thecentral portion of the artificial intervertebral disc, and with theupper 608 a-b and lower surfaces 610 a-b so engaging the inwardly facingsurfaces of the baseplates, causes the baseplates to be placed inparallel orientation with respect to one another.

More particularly, for example for use with the exemplary artificialintervertebral disc of FIGS. 13-20, the upper surface 608 a-b of eachextent is flat, except for a tapered section 612 a-b at the distal tipof the extent, which tapered section narrows the tip, and the lowersurface 610 a-b of each extent is curved to form opposing concavecontours 614 a-b that are cooperatingly shaped to conform against theinwardly facing surface of the convex structure of the artificialintervertebral disc.

The preferred use of the leveler 600 is as follows. As discussed above,once the intervertebral space has been prepared and distracted to adimension that will accept the artificial intervertebral disc to beimplanted, the artificial intervertebral disc 160 is engaged at itslower baseplate 168 b by the inserter/impactor 400,4000 discussed above.During insertion (and, if necessary, impaction) of the artificialintervertebral disc 160 into the intervertebral space, the upperbaseplate 168 a remains free to angulate with respect to the lowerbaseplate 168 b, so that the angulation of the baseplates conforms tothe angulation of the intervertebral space as the artificialintervertebral disc is being inserted thereinto. Typically, theendplates of the prepared and distracted intervertebral space will belordotically angled with respect to one another, due to the use of thestatic trials 100,1000 as described above, which are formed to have alordotic taper as discussed above. Thus, when the artificialintervertebral disc is inserted into the intervertebral space, itsbaseplates will be lordotically angled with respect to one another. Oncethe artificial intervertebral disc 160 is inserted, theinserter/impactor 400,4000 can be disengaged, and therepositioner/extractors 500,510,520,530,540 discussed above can beapplied to the artificial intervertebral disc, if necessary to achieve amore optimal positioning.

Once the positioning is established, the leveler 600 is preferablyapplied to the artificial intervertebral disc 160. The forked distal endof the leveler 600 is inserted so that the extents 604 a-b are placedbetween the inwardly facing surface 164 a of the upper baseplate 168 aand the inwardly facing surface 164 b of the convex structure 162 on thelower baseplate 168 b, and so that the central pocket 606 of the leveler600 avoids the ball-and-socket joint of the artificial intervertebraldisc 160. If the baseplates are lordotically angled with respect to oneanother, the tapered sections 612 a-b of the upper surfaces 608 a-b ofthe forked distal end will be approximately parallel to, and will firstencounter, the angled inwardly facing surface 164 a of the upperbaseplate 168 a. At the same time, the concave contours 614 a-b of thelower surfaces 610 a-b will accommodate the inwardly facing surface 164b of the convex structure 162 on the lower baseplate 168 b. As thetapered sections 612 a-b press against the inwardly facing surface 164 aof the upper baseplate 168 a, and the concave contours 614 a-b slip intoplace against the inwardly facing surface 164 b of the convex structure162 on the lower baseplate 168 b, the tapers 612 a-b will function aswedges to force the posterior portion of the upper baseplate 168 a awayfrom the posterior portion of the lower baseplate 168 b. Accordingly, asthe posterior portions are being separated, the stabilizing spikes 188a-b on the outwardly facing surfaces 186 a-b of the baseplates 168 a-bfind or secure their purchase in the hard bone of the outer ring of thevertebral body endplates. When the forked distal end is fully seated(stops 616 a-b are provided to butt up against the anterior portions ofthe baseplates 168 a-b to prevent the forked distal end from beinginserted too far), the extents of the tongs 604 a-b hold the baseplates168 a-b parallel to one another, and so that the spikes 188 a-b arefully engaged in the endplates. The surgeon then slips the leveler 600out from between the baseplates 168 a-b, and out from the wound andcompletes the procedure. A handle 618 is provided at a proximal end ofthe shaft 602 for pushing, pulling, and otherwise manipulating theleveler 600 as needed.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. An intervertebral spacer device, comprising: a first baseplate havingan outwardly facing surface, an inwardly facing surface and an angledperimeter surface formed between the outwardly facing surface and theinwardly facing surface; a second baseplate having an outwardly facingsurface, an inwardly facing surface, a pocket formed in the inwardlyfacing surface and an angled perimeter surface formed between theoutwardly facing surface and the inwardly facing surface, the angledperimeter surface of the second baseplate corresponding to the angledperimeter surface of the first baseplate; and an intermediary memberconnected to the inwardly facing surface of the first baseplate andhaving an articulating portion adapted to engage the pocket of theinwardly facing surface of the second baseplate to provide relativearticulation between the first and second baseplates, wherein the angledperimeter surface of the first and second baseplates include at leastthree flat surfaces forming two protruding corners, a first of the flatsurfaces of each of the first and second baseplates converging with asecond of the flat surfaces of each of the first and second baseplatesto form a first of the protruding corners of each of the first andsecond baseplates, the first of the flat surfaces of each of the firstand second baseplates also converging with a third of the flat surfacesof each of the first and second baseplates to form a second of theprotruding corners of each of the first and second baseplates, andwherein at least one of the first and second baseplates include a recessassociated with each of the three flat surfaces or one of the protrudingcorners of the at least one of the first and second baseplates.
 2. Theintervertebral spacer device of claim 1, wherein the at least one of thefirst and second baseplates include a recess associated with each of thethree flat surfaces of the at least one of the first and secondbaseplates.
 3. The intervertebral spacer device of claim 1, wherein therecess associated with each of the three flat surfaces of the at leastone of the first and second baseplates forms an opposing recess pairwith a recess associated with each of the three flat surfaces of theother of the at lest one first and second baseplates.
 4. Theintervertebral spacer device of claim 3, wherein the first and secondbaseplates each have three recesses, wherein the recesses define first,second, and third access volumes, respectively, each being aligned withan anterior approach direction, a left antero-lateral approachdirection, and a right antero-lateral approach direction, respectively.5. The intervertebral spacer device of claim 3, wherein each recess ofthe first and second baseplates have walls that define an access volumeto accommodate a tool therein.
 6. The intervertebral spacer device ofclaim 5, wherein the inwardly facing surfaces of the first and secondbaseplates are separated by a spacing having a first width, and whereinthe inwardly facing surface of one of the first or second baseplates andthe walls of the access volume of a recess of the other of the first orsecond baseplates are separated by a spacing having a greater secondwidth.
 7. The intervertebral spacer device of claim 6, wherein the toolincludes a distal shaft having a relevant dimension greater than thefirst width, but less than the greater second width, such that thedistal shaft may be accommodated between the first and second baseplatesonly in an access volume.
 8. An intervertebral spacer device,comprising: a first baseplate having an outwardly facing surface, aninwardly facing surface and an angled perimeter surface formed betweenthe outwardly facing surface and the inwardly facing surface; a secondbaseplate having an outwardly facing surface, an inwardly facingsurface, a pocket formed in the inwardly facing surface and an angledperimeter surface formed between the outwardly facing surface and theinwardly facing surface, the angled perimeter surface of the secondbaseplate corresponding to at least a portion of the angled perimetersurface of the first baseplate; and an intermediary member connected tothe inwardly facing surface of the first baseplate and having anarticulating portion adapted to engage the pocket of the inwardly facingsurface of the second baseplate to provide relative articulation betweenthe first and second baseplates, wherein the angled perimeter surface ofthe first and second baseplates include at least three flat surfacesforming two protruding corners, a first of the flat surfaces of each ofthe first and second baseplates converging with a second of the flatsurfaces of each of the first and second baseplates to form a first ofthe protruding corners of each of the first and second baseplates, thefirst of the flat surfaces of each of the first and second baseplatesalso converging with a third of the flat surfaces of each of the firstand second baseplates to form a second of the protruding corners of eachof the first and second baseplates, and wherein the first and secondbaseplates each include at least three recesses each configured toreceive a portion of a tool such that when the portion of the tool isengaged to a recess of at least one of the first and second baseplates,the three flat perimeter surfaces of the first and second baseplates arealigned.
 9. The intervertebral spacer device of claim 8, wherein therecess associated with each of the three flat surfaces of the at leastone of the first and second baseplates forms an opposing recess pairwith a recess associated with each of the three flat surfaces of theother of the at lest one first and second baseplates.
 10. Theintervertebral spacer device of claim 9, wherein the first and secondbaseplates each have three recesses, wherein the recesses define first,second, and third access volumes, respectively, each being aligned withan anterior approach direction, a left antero-lateral approachdirection, and a right antero-lateral approach direction, respectively.11. The intervertebral spacer device of claim 9, wherein each recess ofthe first and second baseplates have walls that define an access volumeto accommodate a tool therein.
 12. The intervertebral spacer device ofclaim 11, wherein the inwardly facing surfaces of the first and secondbaseplates are separated by a spacing having a first width, wherein theinwardly facing surface of one of the first or second baseplates and thewalls of the access volume of a recess of the other of the first orsecond baseplates are separated by a spacing having a greater secondwidth.
 13. The intervertebral spacer device of claim 12, wherein thetool includes a distal shaft having a relevant dimension greater thanthe first width, but less than the greater second width, such that thedistal shaft may be accommodated between the first and second baseplatesonly in an access volume.
 14. An intervertebral spacer device,comprising: a first baseplate having an outwardly facing surface, aninwardly facing surface and an angled perimeter surface formed betweenthe outwardly facing surface and the inwardly facing surface; a secondbaseplate having an outwardly facing surface, an inwardly facingsurface, a pocket formed in the inwardly facing surface and an angledperimeter surface formed between the outwardly facing surface and theinwardly facing surface, the angled perimeter surface of the secondbaseplate corresponding to at least a portion of the angled perimetersurface of the first baseplate; and an intermediary member connected tothe inwardly facing surface of the first baseplate and having anarticulating portion adapted to engage the pocket of the inwardly facingsurface of the second baseplate to provide relative articulation betweenthe first and second baseplates, wherein the angled perimeter surface ofthe first and second baseplates include at least three flat surfacesforming two protruding corners, a first of the flat surfaces of each ofthe first and second baseplates converging with a second of the flatsurfaces of each of the first and second baseplates to form a first ofthe protruding corners of each of the first and second baseplates, thefirst of the flat surfaces of each of the first and second baseplatesalso converging with a third of the flat surfaces of each of the firstand second baseplates to form a second of the protruding corners of eachof the first and second baseplates, and wherein the first and secondbaseplates each include at least three recesses each configured toengage a portion of a tool such that when the portion of the tool isengaged to a recess of at least one of the first and second baseplates,the first protruding corner of the first baseplate is aligned with thefirst protruding corner of the second baseplate and the secondprotruding corner of the second baseplate is aligned with the secondprotruding corner of the second baseplate.
 15. The intervertebral spacerdevice of claim 14, wherein the recess associated with each of the threeflat surfaces of the at least one of the first and second baseplatesforms an opposing recess pair with a recess associated with each of thethree flat surfaces of the other of the at lest one first and secondbaseplates.
 16. The intervertebral spacer device of claim 15, whereinthe first and second baseplates each have three recesses, wherein therecesses define first, second, and third access volumes, respectively,each being aligned with an anterior approach direction, a leftantero-lateral approach direction, and a right antero-lateral approachdirection, respectively.
 17. The intervertebral spacer device of claim15, wherein each recess of the first and second baseplates have wallsthat define an access volume to accommodate a tool therein.
 18. Theintervertebral spacer device of claim 17, wherein the inwardly facingsurfaces of the first and second baseplates are separated by a spacinghaving a first width, wherein the inwardly facing surface of one of thefirst or second baseplates and the walls of the access volume of arecess of the other of the first or second baseplates are separated by aspacing having a greater second width.
 19. The intervertebral spacerdevice of claim 18, wherein the tool includes a distal shaft having arelevant dimension greater than the first width, but less than thegreater second width, such that the distal shaft may be accommodatedbetween the first and second baseplates only in an access volume.
 20. Anintervertebral spacer device, comprising: a first baseplate having anoutwardly facing surface, an inwardly facing surface and an angledperimeter surface formed between the outwardly facing surface and theinwardly facing surface; a second baseplate having an outwardly facingsurface, an inwardly facing surface, a pocket formed in the inwardlyfacing surface and an angled perimeter surface formed between theoutwardly facing surface and the inwardly facing surface, the angledperimeter surface of the second baseplate corresponding to at least aportion of the angled perimeter surface of the first baseplate; and anintermediary member connected to the inwardly facing surface of thefirst baseplate and having an articulating portion adapted to engage thepocket of the inwardly facing surface of the second baseplate to providerelative articulation between the first and second baseplates, whereinthe angled perimeter surface of the first and second baseplates includeat least three flat surfaces forming two protruding corners, a first ofthe flat surfaces of each of the first and second baseplates convergingwith a second of the flat surfaces of each of the first and secondbaseplates to form a first of the protruding corners of each of thefirst and second baseplates, the first of the flat surfaces of each ofthe first and second baseplates also converging with a third of the flatsurfaces of each of the first and second baseplates to form a second ofthe protruding corners of each of the first and second baseplates; and atool including a central shaft and a distal end, the distal end havingat least one portion extending outwardly therefrom and a central flatsurface oriented perpendicularly to the central shaft of the tool, thecentral flat surface adapted to lie adjacent in a parallel fashion to atleast one of the flat perimeter surfaces of the first and secondbaseplates, the at least one portion of the tool engagable to at leastone of the recesses of the first and second baseplates.